MXPA00001197A - Methods for treating neurological deficits - Google Patents

Abstract

The present invention features methods and compositions for treating a patient who has a neurological deficit. The method can be carried out, for example, by contacting (in vivo or in culture) a neural progenitor cell of the patient's central nervous system (CNS) with a polypeptide that binds the epidermal growth factor (EGF) receptor and directing progeny of the proliferating progenitor cells to migrate en masse to a region of the CNS in which they will reside and function in a manner sufficient to reduce the neurological deficit. The method may include a further step in which the progeny of the neural precursor cells are contacted with a compound that stimulates differentiation.

Description

METHODS FOR TREATING NEUROLOGICAL DEFICIENCIES DESCRIPTION OF THE INVENTION This application claims the benefit from the provisional application with serial number 60 / 055,383, filed on August 4, 1997, which is incorporated herein by reference in its entirety. The field of the invention is the treatment of neurological deficiencies caused by a lesion, disease or a developmental disorder that affects the central nervous system. Neurotrophic factors are peptides that in various ways support the survival, proliferation, differentiation, size, and function of nerve cells (for a review, see Loughlin and Fallon, Neurotrophic Factors, Academic Press, San Diego, CA, 1993). While the number of identified tropical factors or growth factors is always growing, most can be assigned to one or another established family based on their structure or link affinities. It has been shown that growth factors of several families, including the epidermal growth factor (EGF) families, support the dopaminergic neurons of the nigrostriatal system (an area that can be treated according to the methods of the present invention) (for review , see Hefti, J.

Neurobiol. 25: 1418-1435, 1994; Unsicker, Prog. Growth Factor Res. 5: 73-87, 1994). EGF, the founding member of the EGF family, was characterized more than 25 years ago (Savage and Cohen, J. Biol. Chem. 247: 7609-7611, 1972; Savage et al., J. Biol. Chem. 247: 7612-7621, 1972). Since then, additional members have been identified; includes the vaccinia virus growth factor (VGF, Ventatesan et al., J. Virol., 44: 637-646, 1982), myxomavirus growth factor (MGF, Upton et al., J. Virol. 61: 1271 -1275, 1987), the growth factor of Shope fibroma virus (SFGF, Chang et al., Mol.Cell.Biol. 7: 535-540, 1987), amphiphulin (RA; Kimura et al., Na ture 348: 257-260, 1990), the growth factor that binds to heparin and similar to EGF (HB-EGF, Higashiyama et al., Science 251: 936-939, 1991). A common aspect of these factors is an amino acid sequence that contains six cysteines that form three cross-linked disulfides and supports the conservation of a structure that underlies their common ability to bind to the EGF receptor. EGF is by far the most studied member of the family and was the first one located in the brain tissue: EGF-like immunoreactivity (IR) was found in areas of development of the anterior brain of the adult and the midbrain including the pale globe, the ventral pallidum, the entopeduncular nucleus, the substantia nigra, and the Calleja Islands (Fallón et al., Science 224: 1107-1109, 1984). Another member of the EGF family, TGFa, was also located in the brain tissue. It binds to the EGF receptor (Todaro et al., Proc.Nat.Acid.Sci.USA 7_7: 5258-5262, 1980), stimulates the receptor tyrosine kinase activity, and elicits similar mitogenic responses in a wide variety of cell types (for review, see Derinck, Adv. Cancer Res. 58: 21 -52, 1992). TGFa can also bind to additional, unidentified receptors (which may help explain their differential actions in some cells). Previously it has been demonstrated that TGFa-IR is distributed heterogeneously in neuronal pericaria through the adult rat CNS and in the subpopulation of astrocytes of the anterior brain (Code et al., Brain Res. 421: 401-405, 1987; Fallón et al., Growth Factors 2: 241-250, 1990). The mRNA of TGFa has been detected in the entire brain of rodents (Lee et al., Mol.Cell. Biol. 5_: 3655-3646, 1985; Kudlow et al., J. Biol. Chem. 264: 3880- 3883, 1989) and in the striatum and other regions of the brain by means of a nuclease protection assay (Weickert and Blu, Devel. Brain Res. 8_6: 203-216, 1995) and by in situ nucleic acid hybridization ( Seroogy et al., Neuroreport 6: 105-108, 1994).

The mRNAs of TGFa and EGF reach their highest relative abundance (compared to total RNA) in the early postnatal period and then decrease, suggesting that they have a role in development (Lee et al., 1985, supra; Lazar and Blum, J. Neurosci, 12: 1688-1697, 1992). In the totality of the brain, the reduction is greater than 50% (Lazar and Blum, 1992, supra), whereas in the striatum, the relative mRNA of TGFa falls two thirds of the maximum levels (Weickert and Blum, 1995, supra) . At all stages of development examined, the total mRNA of TGFa in the brain exceeds the levels of mRNA of EGF by more than one order of magnitude (Lázaro and Blum, 1992, supra). The EGF receptor was localized by immunocytochemistry to astrocytes and subpopulations of cortical and cerebellar neurons in the brain of rats and in human neurons of autopsy brains (Gomez-Pinilla et al., Brain Res. 438: 385-390, 1988; Werner et al. al., J. Hystochem. Cytochem. 3_ß_: 81-86, 1988). The EGF ligation sites were found in the cortical and subcortical areas of the rat, including the striatum, in an autoradiography study with radiolabeled EGF (Quirion et al., Sinapse 2_: 212-218, 1988). In hybridization studies, if the existence of EGF receptor mRNA was demonstrated in the striatum and ventral mesencephalon cells (Seroogy et al., 1994, supra) and in the proliferative regions in the brain of developing rats or the adult brain (Seroogy et al., Brain Res. 670: 157-164, 1995). As with the mRNA of EGF and TGFα, the mRNA of the EGF receptor is more abundant in the striatum and ventral midbrain in early development and gradually declines as the animal matures (Seroogy et al., 1994, supra). Psychologically, TGFa acts on numerous types of cells throughout the body, including several of neural origin (for review, see Derynck, 1992, supra). It supports the subsistence of central neuron cultures (Morrison et al., Science 238. - 12-15, 1987; Zhang et al., Cell. Regul. 1: 511-521, 1990) and, unlike EGF, improves the subsistence and neurite outgrowth of the sensory neurons of the dorsal root ganglion (Chalazonitis et al., J. Neurosci, 12: 583-594, 1992). It also stimulates the proliferation and differentiation of both progenitor and neuronal progenitor cells from developing brains and adults (Anchan et al., Neuron 6: 923-936, 1991). The trophic effects of peptides of the EGF family in cultures of dopaminergic neurons of the mesencephalon have also been studied in recent years. EGF improves the subsistence of dopamine E16 neurons in mixed cultures of the midbrain (Casper et al., J. Neurosci Res. 3_0_: 372-381, 1991), but the degree to which it stimulates the increase of dopamine. is modest (Knusel et al., J.

Neurosci. 10: 558-570, 1990). TGFa also supports the subsistence of mesencephalon dopamine neurons in dissociated cell cultures, but its effect is more selective than that of EGF (Ferrari et al., J. Neurosci Res 30: 493-497, 1991; Alexi and Hefti, Neurosci 55 ^: 903-918, 1993). Another important feature of the growth factors of the EGF family is its ability to protect the midbrain dopamine cells from neurotoxic assaults. It has been shown that EGF protects dopamine neurons from the excitotoxicity of glutamate or quisqualate in dissociated cell cultures (Casper and Blum, J. Neurochem, 65: 1016-1026, 1995). It has also been shown to protect dopamine cell cultures from the selective neurotoxins of dopamine l-methyl-4-phenylpyridinium (MPP +, Park et al., Brain Res. 599: 83-97, 1992) and to increase the uptake of dopamine in cultures treated with MPP + (Hadj iconstantinou et al., J. Neurochem, 57: 479-482, 1991). The results of studies with EGF in vivo were consistent with those obtained in cultures; EGF performed neuroprotection in both instances. For example, intracerebroventricular infusions (ICVs) of EGF reduced the rotations of the induced amphetamine, increased the number of surviving cells immunoreactive to tyrosine hydroxylase (TH-IR) in the SN, and increased striatal TH-IR fibers after the transection. of the migroestriatal pathway in a PD model rat (Pezzoli et al., Movemen t Disord 6: 281-287, 1993; Ventrella, J. Neurosurg. Sci. _37: 1- 8, 1993). The ICV infusions of EGF in the brains of mice injured with l-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), improved the content of dopamine and 3,4-dihydro-cyphenylacetic acid (DOPAC) ) and the activity of tyrosine hydroxylase in the striatum (Hadj iconstantinou et al., 1991, supra, Scheneider et al., Brain Res. 674: 260-264, 1995). Despite its more potent activity in vi tro, with respect to EGF, the trophic effects of TGFa in vivo - particularly in animals, including humans with neurological deficiencies - have not been determined. The present invention is based on the recently discovered effects of the infusion of TGFα into normal and abnormal (injured) cells of the central nervous system, which are described herein. The present invention features methods and compositions for treating a patient who has neurological deficiencies. The method can be performed, for example, by contacting (in vivo or cultured) a neural progenitor cell of the patient's central nervous system (CNS) with a polypeptide that binds to the epidermal growth factor receptor (EGF) and directing the progeny of proliferating progenitor cells to migrate en masse to a region of the CNS where it can receive and function sufficiently to reduce neurological deficiency. The method may include an additional step in which the progeny of the neural precursor cells are contacted with a compound that stimulates differentiation. Other objects, advantages and novel features of the present invention will become apparent from the brief description of the drawings, from the detailed description of the invention and from the working examples that follow. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic coronal section of the anterior brain of a rat. The injection pipette illustrated on the right side represents a place where the growth factor, the striatum (str), can be infused. (cerebral cortex = ctx; lateral ventricle = lv). Figures 2A-2D are photomicrographs of a coronal section of the midbrain of the brain of an adult rat that was probed to show the distribution of the EGF receptor mRNA. In Figure 2A a "sensitivity" probe was applied as a control. In Figures 2B-2D, sections of the substance nigra (sn) reveal a moderately abundant expression in the hippocampus (hip), the middle portion of the sna, and in the parabranchial and paranigral nucleus of the ventral tegmental area (row). In the most caudal part of the midbrain (Figure 2D), the interpeduncular nucleus (ip) was the most intensely marked. Bar scale = 5mm. Figure 3 is a photomicrograph of a coronal section of the striatum of the adult brain of a rat that was infused with TGFα and probed to show the distribution of the EGF receptor mRNA. On the infusion side, a marked increase in hybridization density is apparent in the medial striatum adjacent to the lateral ventricle. Figure 4 is a photomicrograph of a coronal section of the forebrain of the brain of an adult rat that was infused with TGFα and injured with 6-OHDA. An in-situ hybridization was performed to locate the EGF receptor mRNA, which appears as a pronounced ridge that extends far into the body of the striatum. Figure 5 is a bar graph showing the standardized densities of the hybridization densities of TGFα mRNA in the striae in each of zinc-O groups of animals examined (normal, an infusion of aCSF, without injury, an infusion of aCSF, injury, infusion of TGFα, without injury, infusion of TGFα, lesion). The parallel bars represent the treatment densities in the ipsilateral and contralateral striae. The mean density of the libridation of the treatments was significantly reduced in an ipsilateral quarter, in both groups, which received migraine lesions by 6-OHDA. The striatal infusion of the TGFa peptide had no impact on the reduction. Averages ± S: E: M. (Student's t-test, by pairs for ipsilateral-contralateral comparisons; P values, * p < 0.005, ** p < 0.001). Figure 6 is a bar graph showing the standardized densities of hybridization of EGF receptor mRNA in the subependymal regions along the edges of the striae surrounding the lateral ventricles of animals belonging to the same five groups of tests described in Figure 5. The bars in pairs represent the treatment densities in the ipsilateral and contralateral striae. The average hybridization densities approximately doubled in the ipsilateral subependymal region in both groups that received striatal infusions of TGFα. Averages ± S: E: M. (Student's t test, in pairs for ipsilateral-contralateral comparisons, P values, * p <0.01, ** p <0.0001). Figure 7 is a bar graph showing the standardized average densities of the hybridization of the EGF receptor mRNA in the striatal ridges, the crested body of the striatum and the subependymal regions in all animals with striatal crests. The bars in pairs represent the treatment densities in ipsilateral and contralateral striae. The average densities of hybridization to the treatment were higher in the ipsilateral striatal ridge. The non-striatal crests always appeared in the contralateral striae. Striatal infusions of TGFa. Averages ± S: E: M. (Student's t-test, in pairs for ipsilateral-contralateral comparisons, values P, * p <0.005, ** p <0.001). Figures 8A and 8B are photomicrographs of coronal sections of the striatum of an adult rat that received a migraine injury with 6-OHDA and an infusion of TGFα for fourteen days. In Figure 8A, the silver dyeing of the treatments in the ipsilateral caudate putamen reveals a large number of cells in the dorsal portion of the ridge, many of which exhibit an elongated morphology and are usually oriented towards the subependymal region. There is also an increase in the number of cells along the lateral ventricle (lv). In the contralateral striatum (Figure 8B), the cell population did not expand, neither in the striatum nor along the lateral ventricle. Figures 9A to 9D are photomicrographs of coronal sections stained with thionin, from brains of adult rats, from animals that were injured with 6-OHDA and infused with TGFα for varying periods of time. In Figure 9A, after four days of infusion, the cellular expansion in the subependymal region is scarcely detectable on the background dyeing. In Figure 9B, after six days of infusion, the aggregation of thionin-stained cells near the lateral ventricle is much greater. In Figure 9C, after nine days of infusion, a region of densely stained cells appears slightly next to the subependymal zone at the ventral end of the cell expansion. In Figure 9D, after fourteen days of infusion, a well-formed and dense ridge becomes evident, well inside the body of the striatum. Figures 10A and 10B are photomicrographs of coronal sections of brains of adult rats, of animals that were injured with 6-OHDA and infused with TGFa for fourteen days. In Figure 10A, immunohistochemistry of nestin reveals a pronounced striatal crest. In Figure 10B, thionine staining of adjacent adjacent sections confirms the registration between the nestin-IR cells and the striatal crest. Figures 11A-11C are photomicrographs of coronal sections stained with thionin from an adult rat brain of animals injured with 6-QHDA and infused with TGFα at various distances from the lateral ventricle, for fourteen days. In Figure HA, where the infusion cannula was implanted in the farthest lateral striatum, the ridge runs parallel to the subependymal zone and is less dense than that seen with the median striatal infusion. In Figure 11B, where the infusion cannula was implanted in the mid striatum, the ridge has a characteristic contour of S, with the ventral portion extending well into the ventral striatum. In Figure 11C, in which the infusion was immediately adjacent to the lateral ventricle, the striatal crest is L-shaped and generally exhibits a very dense thionin staining. Figure 12 is a bar graph showing the maximum displacement of the striatal ridge (from the lateral ventricular part, in mm), in coronal sections of the adult rat brain after migraine lesions with 6-OHDA and mean striatal infusions of TGFa for fourteen days. The animals treated according to "Schedule A" (left end bar) received lesions first, followed by infusions of TGFa four or five weeks later. Animals treated according to "Schedule B" received lesions two days after the fourteenth day when the infusion of TGFa began. The averages ± S: E: M. (Student's t test, P values, * p <0.01). I. The Nigrostriatal and Striatum System A. Anatomy, Connectivity and Neurochemistry Within the brain, the striatum, the palidum, the nigra substance, the ventral tegmental area (VTA), the subthalamic nucleus and the amygdala are collectively referred to as basal ganglia. The striatum contains dorsal and ventral components, each of which is still subdivided into additional anatomical structures. In humans, the dorsal striatum consists of the caudate nucleus and the putamen. The C-shaped caudate follows the curve of the lateral ventricles. The portions of its tail extend up past the lower horns and join with the amygdala in each temporal lobe. The head of the caudate becomes ventral from the anterior end of the anterior horns and merges with the putamen. Although anatomically it is quite different in the human brain, in rodents, the caudate putamen or caudoputamen are combined in a common structure. The ventral striatum consists of the acoustic nuclei, the olfactory tubercle and associated striatal cell bridges. The palidum includes the globus pallidus, the entopeduncular nucleus, the reticulated part of the substantia nigra (SNr), and the ventral pallidum. The entopeduncular nucleus and the SNr have very similar afferent and efferent connections. The ventral pallidum contains regions that have a mixture of connections that are similar to both the globus pallidus and the entopeduncular nucleus. The other part of the substantia nigra, the compact part (SNc), includes dopamine neurons that include the tegmental area of the ventral substantia nigra (SN-VTA), as well as clusters of dopamine cells in the SNr. The set of circuits of the basal ganglia is complex, but is very similar in both humans and rats (Fallon and Loughlin, Cerebral Cortex EG Jones and A. Peters, Eds., Vol. 6, pp. 41-127, Plenum Press , New York, 1987; Alheid and Heimer, Progr. Brain Res. 107: 461-484, 1996), making the rat a useful model to study the connections, neurochemistry, pharmacology, function and clinical correlations of this system in the brain. of mammals. The striatum, together with other nuclei of the basal ganglia, contributes to the regulation of movement and emotion. A number of diseases that affect the system or its innervations have been associated with motor impairment that weakens deeply, often accompanied by affective disorders. Caudate and putamen are the primary blood supplies of the basal ganglia and receive higher excitation projections from the cerebral cortex and the centromedial and intralaminar nuclei of the thalamus. Corticostriatal afferents are glutamatergic. It is also thought that the afferents of the thalamus are glutamatergic. The compact part of the substance nigra (SNc), provides a dense supply of dopaminergic blood to the striatum, through the nigrostriatal pathway (for review of the system in the rat, see Fallón and Loughlin, The Rat Nervous System, G. Paxinos, Ed., Pp. 215-237, Academic Press, San Diego, 1995). The ventral striatum and the acoustic nuclei receive most of their dopaminergic innervation from the VTA dopamine cells in the ventiomedial mesencephalon. The limbic afferents of the amygdala and the serotorn fibers. i / ojicas of the midbrain or raphe also end in the ventral striatum. The distribution of striatal afferents and their endings are not simply uniform representations of their regions of origin. The striaturn is organized in embedded pieces or striosomes fitted <;.or. a functional and chemically distinct surrounding matrix. This organization was originally demonstrated using histochemistry in acetyl cholinesterase (AChE), which selectively stains the matrix (Graybiel and Ragsdale, Proc. Na ti.Acid. Sci. USA, 7_5: 5723-5726, 1978). Since then, the stoichiometry of the enzyme, immunocytochemistry, in-situ hybridization, radiolabeled ligand ligand receptors, anterograde degeneration and many other methods have been used to identify many additional markers that are differentially distributed in the two compartments. Matrix markers include calbindin, somatostatin, and dopamine elevation sites (H) mazindol ligation) (Gerfen, J. Comp.Neurol., 236: 454-476, 1985; Voorn et al., J Comp.Neurol. 289: 189-201, 198 .. Striosomes can be identified by their abundance of high enkephalin, activity of 5'-nucleotidase in migroestriatal lesions, hydroxylase tyrosin, the mu-opoid binding receptor, and substance P (Graybiel et al., Neurosci., 6: 377-397, 1981, Schoen and Graybiel, J. Comp.Neurol., 322: 566-576, 1992.) As might be expected, however, there are interspecific variations and development in several of these markers and some are useful only in certain regions of the striatum.The heterogeneity of the chemical markers is much more complicated due to the origin and selective terminations of several striatal pathways in the compartments of the embedded pieces or in that of the matrix For example, afferents d The motor, singular, somatosensory and visual areas of the cortex end in the matrix (Gerfen, Na ture 311: 461-464, 1984: Donoghue and Herkenham, Bra in Res. 365: 397-4Q3, 1986). Most of the corticostriatal afferents of the deep layer V and of the layer VI of the limbic cortex end in eml'pr.idas pieces while the superficial layer V and ae of the layers II and III provide the blood supply to the matrix (Gerfen, Science 246: 385-388, 1989). The afferents of the VTA and the dorsal row of the SNc provide dopaminergic blood supply to the matrix. Sausage pieces receive dopamine innervation from the ventral row of the SNc and from the clusters of dopamine cells in the SNr (Schoen and Graybiel, J. Comp.Neurol, 322: 566-576, 1992). In the dorsal striatum, supplies of blood from the nuclei in the medial division of the thalamus terminate in emuced pieces, while the afferents of the lateral division - including the third anterior and posterior intralaminar ventral rostral nucleus - predominantly innervate the tissue of the matrix (Regsdale and Graybiel, J. Comp.Neurol. 311_: 134-167, 1991). Additionally, the amygdalostriatal fibers originate the compartment of the embossed pieces, in the vasolateral nucleus of the selectively innervated tonsil (Regsdale and Graybiel, J. Comp.Neurol., 269: 506-522, 1988). The striatal efferents are also distributed differently with respect to the organism 'i' > r. of the pieces embedded in the matrix. It has been shown that the striatonigral pathway, one of the two major pathways that originate in the striatum, is composed of two different projections. The fibers that arise from the neurons in the compartment of the embossed pieces terminate around the dopamine neurons in the ventral SNc and in the Lucimos of dopamine cells in the SNr. The neurons of the matrix give rise to topographically arranged projections in the SNr, including non-dopaminergic areas and dopamine neurons whose dendrites are located in the SNr íc-rfen, 1984, upra; Jimenez-Castallanos and Graybiel, Neu osci. 32: 297-321, 1989). The other main efferent projection, the striatopalidal way, is projected towards the globus pallidus. Mo has been shown to have a distribution related to the organization of the pieces embedded in the matri'_; however, it is distinct neurochemically from the striatonigral system. The majority of the striatopalidal fibers have a pattern and not a dynorphin or P substance. In contrast, few striatonigral projections contain encephalitis, and many express dynorphin and substance P.Gerfen and Young Bra in Res. 460: 161-167, 1088). In primates, .. >; > . • _. two systems also differ in their anatomical regions of origin: the striatopalidal efferents arise mainly from the putamen while the striatonigral efferents originate primarily in the caudate (Parent et al., Bra in Res. 303: 385-390, 1984). In addition to the heterogeneous distribution of the striatal connections, several morphologically and chemically distinct neurons have been found in the striatum(Albin et al., Trends Neurosci. 12_: 336-375, 1989; Groves, Brain Res. Rev. 5: 234-238, 1983). They are traditionally classified as spiny or non-spiny based on their dendritic morphology. There are generally two recognized types of spiny neurons in the striatum. They contain several combinations of GABA, substance P, enkephalin and dynorphin, but they are predominantly GABAergic. The thorny nonsigns of the medium (thorny type I) are by far the most abundant, ranging from 90 to 95% of all striatal neurons. They have smooth, cellular bodies and dense accumulations of spines in the distant portions of their dendrites. Their dendritic arborizations reach around 200 μm of the soma. Spinal neurons of the medium r.ov. the main terminal target of the dopaminergic neurons in the SNc, those that synapse predominantly with the necks of the dendritic spines. Spinal neurons of type II are much larger, with variable enramadas that extend up to around 600 μm of the soma. The spiny neurons are the projections -i-; the neurons of the striatum. These project predominantly towards the inner segment of the globus pallidus (GPi) and towards the SNr, in the matrix containing GABA and substance P. The spiny GABAergic neurons of the matrix containing the lectin, on the other hand, innervate the outer segment of the globus pallidus (GPe). The spiny neurons - in the compartment of the embossed pieces send most of their efferents to the SNc (Albin et al., 1989, supra). The striatal projection neurons of the two major efferent pathways can also be distinguished by their dopamine receptor subtypes. The neurons of substance p / dynorphin that project towards the substance nigra, express predominantly dopamine Dj receptors, whereas the striatopalidal neurons teach mainly receptors D? . No you; of receptor, however, is expressed exclusively in some of the projections (Besson et al., Neurosci., 2_6: 101-119, 1989; Gerfen et al., Science 2 ^ 0: 1429-1432, 1990). Three recognized types of non-spiny neurons make up the population of striatal interneurons (Groves, 1983, supra; Carpenter, In: Core Te: -: t of Neurosciences, pp. 325-360, Williams and Wilkins, Ball.imore, 1991). Together, they make up 10% or less of the total number of striatum neurons. Non-spiny neurons of type I are the most common of the three types and have smooth dendrites enramadas a little smaller than those of the spiny neurons in the middle. They are widely GABAergic, but arias contain somatostatin and neuropeptide Y. Non-spiny neurons of type II can be distinguished by their broad cell bodies and by their staining of AChE and choline acetyltransferase (ChAT). This type of cells form symmetrical synapses with the spiny neurons of the medium. The non-thorny neurons of type III of the medium are the least characterized, but they are thought to contain GABA. There are probably additional subgroups of neurons of this same class, defined chemically and conexionally, in addition to those that have already been identified. B. Topography and Development Experiments with retrograde and retrograde harrows in the striatal projections of the mesencephalic dopamine system revealed precise topographies in adult rodents (Fallón and Moore, J. Comp.Neurol., 180: 545-580, 1978). The dorsal extriatum receives dopaminergic innervation of neurons of the SN and ventral and intermediate VTA. The ventral striatum and the acoustic nuclei receive dopaminergic blood supply from the dorsal VTA and the intermediate SN (Fallón, Ann. NY Acad. Sci. 537: 1-9, L988). The neurogeneic gradients in the development system go parallel with the topographic arrangements of the projections in the mature system. The dorsolateral portion of the SN is the first to be produced in the embryo, before embryonic day 15 (E15) in the rat (Altman and Bayer, J. Comp.Neurol. 198_: 677-716, 1981). The projections of this region, innervate the lateral and ventral regions of the striatum (Cárter and Fibiger, Neurosci. '' 1: 569-576, 1997; Veening et al. , Neurosci. 5: 1253-1269, 1980), which are also the striatal areas generated earlier (Bayer, Neurosci 4: 251-271, 1984). As the striatum is populated with young neurons in a ventrolateral to dorsomedial gradient, the afferents arrive from more dentromedial (and later produced) portions of the SN (generated after E15), to innervate these striatal areas produced later. Therefore, the younger nigral dopamine neurons (ventromediai), innervate the younger striatal irons (dorsomedial), and the older dopamine nigral neurons (dorsolateral) innervate the older striatum neurons (entrolateral). This pattern is repeated in the GABAergic striatonigral projections, too (Bunney and Aghajanian, Bra iz Res. LT7_: 423-435, 1976). The striatum neurons are derived from an auroepithelium that surrounds the lateral ventricles in the prenatal and early postnatal brain. A ventricular zone initially borders the ventricles, later the subventricular (or subependymal) zone is incorporated deep within them. As the brain matures, the ventricular zone disappears but the subependymal zone persists as a thin layer of cells. This zone contains neural cells, offspring and progenitor cells that migrate along a defined and restricted pathway, to replenish the skillful population of interneuronal cells of the olfactory bulb (Luskin, Neuron 1: 1: 173-189, 1993; Lois and Alvarez). -Buylla, Science 264: 1145-1148, 1994). C. Pathology Striatum and its dopaminergic innervations are vulnerable to a number of conditions including several neurodegenerative diseases (Albin et al., 1989, supra), such as Huntington's disease (HD) and Parkinson's disease (PD). HD is an autosomal dominant hereditary disease (chromosome 4), characterized by the progressive degeneration of the striatum. It is associated with involuntary chorealetotic movements of the limbs and the face and with disorganization of the voluntary movement (for review, see Purdon et al., J. Psychiatrics Neurosci.16: 359-367, 1994). The GABAergic and medium spiny neurons in the matrix compartment are most affected, especially the GABA / encephalinergic neurons, which project towards the GPe (Albin et al., 1989, supra). The broader non-spiny polyneuronal interneurons and the small non-spiny interneurons containing somatostatin, the neuropeptide Y and NADPH-diaphorase, also found in the matrix compartment, are relatively -soasas (Ferrante et al., Science 230: 561-563 , 1985; Reiner er. Al., Proc. Na ti. Acad. Sci. USA 8_5: 5733-5737, 1988). In a more advanced phase of HD, however, neuronal degeneration includes all types of striatal neurons and extends to other nuclei of the basal ganglia, the cerebral cortex, hypothalamus and cerebellum.

Parkinson's disease (PD) is characterized by tremor at rest, rigidity, inability to initiate movement (akinesia), and slow movement (bradykinesia) (Marsden, Lance t 336: 948-952, 1990). Motor deficits are associated with the progressive degeneration of the dopaminergic nigrostriatal pathway and in various degrees such as the loss of dopaminergic innervation of the abundant nuclei and the degeneration of the < -noradrenergic cells of locus ceruleus and raphe neurons (Javoy-Agid et al., Adv. Neurol. 40: 189-198, 1984; Agid, Lancet 337: 1321-1327, 1991). Up to 80% of the nigral dopamine neurons can be lost before significant motor impairments manifest. One of the major strategies for using the peptides known as neurotrophic factors, as therapeutic agents in the treatment of neurodegenerative diseases, is to stop the degenerative process and improve the function of the cells that remain. The studies presented in the examples below will illustrate how the present invention expands the use of neurotrophic factors beyond what had previously been suggested. II. Treatment of Meurological Deficiencies As demonstrated by the examples in the following, the neural precursors of the subependymal areas of the adult forebrain can be stimulated to proliferate and migrate en masse to the central nervous system (CNS) (for example in the striatum) in response to an infusion of a polypeptide that binds the EGF receptor (e.g. TGFa, the term "polypeptide" as used herein, refers to any chain of amino acid residues, regardless of length or modification after the translation). Still further, the migration of proliferating cells can be directed as a dense ridge. As described in the following, directed migration can be carried out in a variety of ways. For example, it is facilitated by the enervation of the target region (which can be achieved by neurochemical means or mechanical forces), by the application of a polypeptide that is a growth factor (for example, TGFβ, which increases the regional expression of the cell adhesion such as fibronectin, and laminin) and by contacting cells that are along a desired migratory pathway with a compound that inhibits the occurrence of a natural signal that would inhibit migration in another way (i.e. , creating a permissive microenvironment by inhibiting an inhibitor).

On the other hand, the profile of the migratory ridge can be controlled by varying the location of the infusion (for example, by altering the collation of the infusion cannula of a biodegradable capsule containing the active compound or compounds of the invention). Similarly, the number of cells within the ridge can be controlled by varying the dosage of the active compound or compounds (eg, the dosage of TGFa) or the distance at which it is released with respect to the population of precursor cells. neural diseases in the subependymal region. As described in the following (and as illustrated in Figures 10A, 10B, HA, 11B, and 11C), when the animals received medium striatal or medial stratial infusions, the migratory cells were stopped before they had reached the infusion cannula, which resulted in the S-shaped or L-shaped crest. Therefore, it is possible not only to facilitate the migration of the cells, but also to control where the migration ends. The adjustment of the dose and the location of the release of the growth factor (and perhaps of other compounds), can allow to restrict the gestated area to a relatively limited target area. The proliferation and migration of neural precursor cells in the brain of adult mammals are distinct events that can be controlled separately.

Intracerebroventricular (ICV) or intrastriatal infusions of TGFα or EGF without deafference may induce proliferation, but degenerative cells, damaged (eg, by deafiation or other injury, or abnormal in some other way) must be present (ie, that they work poorly), to facilitate migration, at least on a scale that is sufficiently broad to promote the re-establishment of an associated neurological deficiency.As described below, the 'facilitating effect of degenerative, damaged cells can be mimicked or abnormal in some other way, with pharmacological agents, for example, the transient expression of cell adhesion molecules in the striatum can be stimulated by administering a compound that induces it, for example, fibronectin is highly controlled because it transforms the facu beta growth in cultures of cerebellar astrocytes (TGFß) (Baghdassarian et al., Gl ia 7: 193-202, 1993). Transgenic overexpressing TGFβ, fibronectin and laminin also increase strongly in the CNS above normal levels (Wyss-Coray e t a l. ,? m. J. Pa thol. 147: 53-67, 1995). Therefore, directed migration with any compound that stimulates the expression of extracellular matrix molecules or cell adhesion molecules, particularly along the desired migration pathway, is considered within the scope of the present invention. It is believed that neural stem cells of the forebrain, which give birth to progenitors that migrate, remain in place along the ventricular wall (Morshead et al., Neuron 13: 1071-1082, 1994). In the experiments described in the following, a region of intense hybridization of the EGF receptor persisted along the lateral ventricle after the migratory crest had moved towards the striatum. In addition, elongated cells were always found between the ridge and the lateral ventricle. Therefore, despite the massive migration of cells away from the subependymal zone, the stem cells themselves were probably not part of the migratory ridge. These stem neural cells would provide a renewable source of neurons and glia. Therefore, multiple waves of progenitor neural cells can be stimulated to migrate to regions of the brain that are injured or degenerated or that contribute in some other way - or a neurological deficiency. The persistence of these cells also suggests that the normal functions of the stem cells in the adult forebrain - which today is believed to provide new neurons for the olfactory bulbs - should not be interrupted irreversibly by the treatments.

Abundant striatal expression of TGFα (and its mRNA) and an absence of dopamine-like enervation characterize the early developmental striatum (Weickert and Blum, Devel. Brain Res. 8_6: 203-216, 1995; Bayer, Intl. J. Devel. Neurosci.2: 163-175, 1984). Similarly, increased expression of the EGF receptor mRNA in the subependymal region in animals infused with TGFa emitted abundant hybridization of the EGF receptor mRNA, observed in the periventricular neuroepithelium in the developing brain (Seroogy et al., Neuroreport _6: 105- 108, 1994; Seroogy er al., Brain Res. 670: 157-164, 1995). The forms that encode the messenger RNAs of fibronectin and its receptor, and other cell adhesion molecules, which facilitate the migration of neural precursors, are extensively regulated (Pesheva et al., J. Neurosci Res. : 420-430, 1988, Prieto et al., J. Cell Biol. 111: 685-698, 1990, Pagani et al., J. Cell Biol. 113: 1223-1229, Linnemann et al., Int. Devel. Neurosci.1_1: 71-81, 1993). Therefore, one way to conceptualize the effects observed in animals infused with TGFα and injured with 6-OHDA in the present study is to make a selective recapitulation of embryogenic neurogenesis. That is, neural stem cells in the brains of adult mammals can respond to proliferation signals and their progeny can respond to migration signals as developing animals do. The stem neural cells have recently been found in subependymal cells through the CNS <; The adult rodents (Weiss, Soc. Neurosci, Abs tr. 25_: 101, 1995, Ray et al., Soc. Neurosci, Abs tr. 2_2: 394.5, 1996) and in the subependymal cells of the adult human anterior brain (Kirschenbaum et al., Cerebral Cortex 4_: 576-589, 1994). According to the methods described herein, these cells can be manipulated to provide a source of new neurons for diseased, injured or otherwise damaged or malfunctioning neurons of the CNS, in various regions of the brain and spinal cord. . A. ADVANTAGES OF THIS PRESENTATION As described below, one of the proposed techniques for the treatment of neurological deficiency involves the removal of neural precursors from a patient who has such a deficiency and grows these cells in a culture to generate a large number of neural progenitors. The cells can then be reimplanted in the same patient using technique known to those skilled in the art (for example, see Stein et al., In: Brain Repair, pp. 87-103, Oxford University Press, New York, 1995, or Leavitt et al., Soc. Neurosci, Abs tr. 22: 505, 1996). Clearly, this technique is advantageous with respect to those that are used in the present, and which require embryonic cells from aborted fetuses; completely ethical issues raised by the need to use aborted fetuses as tissue donors. Additionally, it is more likely to succeed because it will not stimulate the immune response that is responsible for a high incidence of transplant rejection. Stimulating the proliferation and migration of neural precursors in vivo has additional advantages; In vivo stimulation reduces the extent and possibly the number of invasive neurosurgical procedures. No excision surgery. of the stem cells will be carried out and you will not need multiple plasters of transo! before cellular, which are typically required with embryonic cells or with the grafts of cultured cells. Furthermore, there will not be a massive, death of undifferentiated progenitor stem cells due to the transplant procedure. Typically, with dopaminergic human fetus grafts, 90% to 99% of the implanted cells die before they become established in the host brain (Freed et al., Soc. Neurosci, Abs tr.22: 481.3, 1996). Another advantage provided by the present invention is that the neural progenitor cells will not be isolated from the host brain by scar tissue. In parts of transplanted cells, it is encapsulated in a sheath of glycystic scar tissue and reactive astrocytes. In addition to the physical barrier of dense glial tissue, reactive astrocytes within the scar tissue release factors that inhibit neurite growth (McKeon et al., L999). The neural progenitors created in vivo are not isolated from the rest of the brain by scar tissue. The excrescence of their neurites, for this reason, will not be inhibited by a massive proliferation or reactive atrocytes. That is why the directed migration provided herein allows the selective repopulation (which may vary in extent) of specific CNS injured regions with a large number of new cells, without disturbing the non-injured areas. The techniques presented herein also represent an advance over the only previous study of neural stem cells of the forebrain stimulated in vivo. In this study, adult rats received ICV infusions of EGF for six days and were followed up for up to seven weeks after the infusion (Craig et al., J. Neurosci, 16: 2649-2658, 1996). In the present study, TGFα was infused for 14 days and followed up for up to 3 months after the infusion ended. This difference is critical, because only in the present study, the cells of the periventricular expansion migrate en masse towards the superadying stratium. The mass-directed migration of the neural progenitors to a chosen target area. represents a much more preferred method to reprobate the degenerative regions of the brain with new neurons. An area of intense interest recently, is the manipulation of the neural stem cell differentiation. Both the final location and the neurochemical phenotypes of the cells, once they have differentiated, are of primary importance and are discussed later. When the neural precursor cells were removed from the brains of adult rodents and differentiated in vi tro, the immuniometrically identified cells such as astrocytes, oligodendrocytes and neurons were seen (Reynolds and Weiss, Science 255: 1707-1710, 1992; Reynolds et al. al., J. Neurosci 12: 4565-4574, 1992, Lors and Alvarez-Buylla, Proc. Na ti. Acad. Sci. USA 9_0: 2074-2077, 1993). Many of the cells identified as neurons were also immune reactive to GABA and substance P, which are neurochemical markers for two types of cells normally found in striatum. The explanted precursor cells of the adult human brain also expressed neuronal markers and showed electrophysiological properties associated with neurons (Kirschenbaum et al., Cerebral Corte :: _4: 576-589, 1994). These experiments suggest that when striatal crest cells differentiate spontaneously in vi, many of them will become cells with phenotypes typical of striatal neurons. Some recent data suggest that their phenotypes may be altered by exposure to different combinations of neurotrophins (Lachyankar et al., Soc. Neurosci, Abstr. 22: 394.7, 1996). The progenitor cells that receive different treatments, express different neurochemical immunomarkers once they have differentiated, including acetyl cholinesterase; GABA, tyrosine hydroxylase (TH), and calbindin. The expression of HT was particularly interesting, since the combination of proliferation, migration and differentiation directed towards the dopamine cell, could provide a new method to replace the losses of dopamine • -n stretch marks in Parkinson's disease (PD ). In PD patients, significant functional numbers of new striatal cells that produce dopamine, would help in the reversal of motor impairments in a manner similar to mid-brain tissue transplants of an aborted fetus. Patients with Huntington's disease (HD), neural precursors will be stimulated to repopulate the striatum with new GABAergic spiny neurons from the medium and other neurons lost in the disease. Some recent evidence from a different line of research indicates that reconstruction of the striatal-palpation pathway itself may be possible. Progenitor neural cells conditionally immortalized, transplanted into the striatum, differentiated and sent to a process, from the striatum to the globus p.iLíidus (Lundberg et al., 1996). B ^ Neurological Deficiencies Subjected to Treatment Because the invention remains in the discovery that multipotent precursor cells can be stimulated to divide and migrate through the brain, it can be used to treat neurological deficiencies caused by a wide variety of diseases, disorders and injuries. These grievances include, but are not limited to, the following (others skilled in the art will be able to categorize differently the diseases and disorders listed in the following: categorized in whatever manner, the neurological deficiencies with which they are associated are subject to treatment of according to the methods of the present invention). 1. Degenerative Diseases Degenerative diseases that can be treated according to the methods of the invention which include Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), Pick's disease , progressive stipranuclear palsy (PSP), striatonigral degerations, cortico-basal degeneration, childhood disintegrative disorder, oligovopontocerebellar atrophy (OPCA); including the hereditary form), Leigh's disease, infantile necrotizing encephalomyelitis, Huntei's disease, mucopolysaccharidosis, several leukodystrophies (such as Krabbe's disease, Pelizaeus-Merzbacher's disease and the like), the amauretic (familial) idiocy , Kuf's disease, Spielmayer-Vogt's disease, Tay Sachs disease, Batten's disease, Jtnsky-Bielschowsky's disease, Reye's disease, ataxia cerebr J, chronic alcoholism, beriberi, Hallervorden-Spatz, cerebellar degeneration and the like. 2. Traumatic and Meurotoxic Lesions to the Central Nervous System Neurotoxic and traumatic injuries that can be treated according to the methods of treatment that include bullet wounds, injuries caused by brute force, injuries caused by penetrating injuries (for example , knife wounds), injuries caused in the course of a surgical procedure (eg, removing a tumor or abscesses of the CNS or treating epilepsies), poisoning (eg, with MPTP or carbon monoxide), agitated baby syndrome, adverse reactions to a drug (including idiosyncratic reactions), drug overdose (eg, dianfetamines), encephalopathy.;? post-traumatic and similar. 3. Ischemia Any interruption of blood flow or oxygen delivery to the nervous system can injure the cells, including the neuronal and gual cells, in the present. These lesions can be treated according to the methods of the present invention and include injuries caused by a fulminating attack (including a global attack (such as that which may result from cardiac arrest, arrhythmia or myocardial infarction) or a targeted attack (as would be expected). of a thrombus, clot, hemorrhage, or other arterial blockage), anoxia, hypoxia, partial drowning, myoclonus, severe inhalation of smoke, dystonias (including hereditary dystonias), acquired hydrocephalus, and the like. 4. Developmental Disorders Developmental disorders that can be treated according to the methods of the invention include eczema, certain forms of severe mental retardation, cerebral palsy (whether caused by infection, anoxia, premature birth, blood type incompatibility: etc. Or whether it manifests as blindness, deafness, retardation, motor skill deficiency, etc.), congenital hydrocephalus, metabolic disorders that affect the CNS, severe autism, Down syndrome, hypothalamic disorder / LHRH, spina bifida and Similar. 5. Disorders Affecting Vision Disorders that affect vision, particularly those caused by the loss or failure of refinal cells, can be treated according to the methods of the invention. These disorders include diabetic retinopathy, serious retinal detachment, retinal damage associated with glaucoma, traumatic damage to the retina, retinal vascular occlusion, degeneration of the macula, inherited retinal dystrophies, optic nerve atrophy and other degenerative diseases of the retina. 6 Spinal Cord Injuries and Diseases Injuries to or diseases that affect the spinal cord can also be treated according to the methods of the invention. Such injuries or diseases include post-polio syndrome, lateral amyotrophic sclerosis, non-specific spinal degeneration, traumatic injury (such as those caused by automobile or sports accidents), including a partially or severely severe crush injury, or that of any other form adversely accept the function of spinal cord cells), injuries caused by spinal cord surgery (eg, removing a tumor), disease of the anterior horn cells, paralysis diseases, and the like. 7. Autoimmune Disorders or Demyelination Neurological deficiencies caused by a demyelination or an autoimmune response can be treated according to the methods of the invention. Such deficiencies can be caused by multiple sclerosis, possible lupus and others. 8. Infectious or Infectious Diseases Neurological deficiencies caused by an infection or an inflammatory disease can be treated according to the methods of the invention. Infectious or inflammatory diseases that can cause treatable deficiencies include Creutzfeldt-Jacob and other infectious diseases lentus virus encephalopathy AIDS AIDS, Parkinson after encephalitis, viral encephalitis, bacterial meningitis and meningitis caused by other organisms, phlebitis and thrombophlebitis of the intracranial sinuses, syphilitic Parkinsonism, CNS tuberculosis and the like. 9. Miscellaneous Those skilled in the art are able to recognize neurological deficiencies, despite the cause they have and to apply the methods of the present invention to treat patients who have such deficiencies. In addition to the conditions listed above, which are subjected to treatment with the methods described herein, neurological deficits may be caused by the Lesch-Nyhan syndrome, myasthenia gravis, various dementias, numerous parasitic diseases, epilepsy and Similar. The methods of the invention can be easily applied to alleviate the neurological deficiencies caused by these or other diseases, disorders or injuries. C. Polypeptides That Link the Receptor? GF! _._ The Family? GF Polypeptides in the EGF family appear in some unrelated way. For example, TGFa and EGF have only 30% structural homology (Marquardt et al., Science 223: 1079-1082, 1984). However, they show similar kinetic ligations for and stimulate tyrosine phosphorylation specific to the membrane receptor Mr 180,000 EGF (Cohen et al., J. Biol. Chem. 255: 4834-4842, 1980; Reynolds et al. , Na ture 292: 259,262, 1981). The functional equivalence of the two growth factors is partially attributed to the same relative positions of the six residue cysteines, represented by "C" in the consensus sequence: CX7CX4.5CXa.0CX CX8C. These conserved residues impose structural constraints similar to disulfide mediated by a bond and therefore, a related three-dimensional structure (Twardzik et al., Proc. Na ti.

Acad. Sci. USA 82: 5300-5304, 1985). Those skilled in the art are able to compare any given amino acid sequence with the consensus sequence of the EGF family to determine whether a polypeptide is probably the functional equivalent of EGF (and if so, useful for practicing the methods of the present invention). invention) (see, for example, Blomquist et al., Proc. Na ti, Acad. Sci. USA 81: 1363-1361, 1984, for a description of a computer investigation that revealed a similar pattern of cysteine and glycine residues. in the EGF, TGFa, and the sequence • ¡e an early 19 kDa protein of the vaccine virus). In addition to EGF, TGFa, and vaccine growth factor (VGF), the EGF family is known to include amforegulin (AR), betacellulin (BTC), epiregulin (ER), the parina binding of the growth factor that is similar to EGF (HB-EGF), neurinoma-derived growth factor (SDGF), growth factor of the avirus HUS 19878, growth factor of the fibroma virus Shope and the growth factor derived from teratocarcinoma -1 (TDGF-1, also known as Crypto-1 (CR-1) 2. Methods for the Determination of Receptor Ligation GF Those skilled in the art are able to determine whether any given polypeptide binds the EGF receptor. As used herein, the term "link" refers to any specific interaction between a polypeptide and an EGF receptor that results in a transduction signal sufficient to produce a biological response, preferably a response that contributes to the reduction of neurological deficiency. Preferably, any given polypeptide useful in the methods of the present invention will bind to the EGF receptor with an affinity that is equivalent to at least 50%, more preferably at least 70%, and more preferably at least 90% of the units of ligation of the EGF itself (see Twardzik et al., supra for a comparison of the biological activity d < -1 VGF, TGFa, EGF in the EGF receptor ligation). Guidance is required to perform a EGF receptor ligation assay, those skilled in the art can consult any of the numerous publications that describe an appropriate procedure (the five publications on this topic that follow, are incorporated herein for reference and completeness. For example, you can consult Cohen and Carpenter, Proc. Na ti, Acad. Sci. USA 7_2: 1317-1321, 1975) or, for a modification of it, Twardzik et al. , supra. Similarly, for a review of the EGF receptor, including specific ligation and information on the sequence, indicating the topology of the receptors, one can consulate, for example, Mclnnes and sykes (Biopolymers 43: 339-366, 1997) Boonstra et al. . , (Cell Biol. In tl., 19: 413-430, 1995), or Gill (Mol. Reproel, Dev. 27: 46-53, 1990). D. Directed Migration The examples in the following also provide evidence for the successful directed migration of neural precursor cells, particularly in the anterior brain of an adult rodent. Immunohistochemistry and other techniques employed in the examples of work in the following (and extensively described herein), as well as comparable techniques routinely carried out by those skilled in the art, can be used to characterize the effect of any infusion of a factor. of growth or other stimulus applied to direct cell migration. Indeed, it is possible to delineate the migration of the cells in some detail (that is, the number of cells, their size, shapes and position within the nervous system can be determined). A variety of stimuli can be applied to the cells in vivo to direct their mass migration (the term "en masse", when used herein to describe cell migration, refers to the movement of a population of cells substantially in the same direction for a sufficient period of time to visualize it as mass (as, for example, is apparent in Figures 9, 10, and 11)). In general, migration can be directed in one of two ways: (1) in a conducive way, that is, by applying a stimulus that positively attracts the migration of the cells (such as a chemoattran e, a neurotrophic factor, or a compound (ie TGFP-) that increases the expression of cell adhesion molecules or of an extracellular matrix molecule (eg, fibronectin, laminin, or a neural cell adhesion molecule)), or (2) a permissive way, that is, by applying a stimulus that inhibits a signal that would otherwise inhibit the migration of the cells. The stimuli that direct the migration include the disruption of the tissue in the target area (which may be the site where the cells have been damaged, ie, the striatum or substantia nigra, where it is known that dopaminergic cells have been lost due to a certain number of debilitating neurodegenerative diseases; the cerebral cortex, where neurons and glias have been lost after an ischemic episode caused for example by a thrombus, a clot; or the spinal cord, where motor neurons have been lost due to, for example, a traumatic injury; or it can be any site where the cells make abnormal connections due to a developmental disorder). Alternatively, the tissue may be broken at or along the pathway extending from the source of the neural progenitor cells to the desired end point. Tissues can be broken by physical force (for example, neurons that are ablated or excised, or by exacerbating one or more of the processes that extend from the bodies of neuronal cells) or by applying a chemical such as a toxin. or neurotoxin (eg, ricin or 6-OHDA), a corrosive chemical (eg, an acidic or basic solution), a compound that induces apoptosis (see, e.g., Leavitt et al., Soc. Neurosci. Abs tr. 2_2: 505, 1996), a compound that induces demyelination (see for example Lachapelle et al., Soc. Neurosci, Abs tr. _2_3: 1689, 1997), or a compound capable of inhibiting the activity of the cell for example an antisense oligonucleotide (such as an oligonucleotide that inhibits the transcription of the gene encoding the primary neurotransmitter of the cell, or an antibody, or a polypeptide.) Many of these compounds are known to those of ordinary skill in the art and include compounds. > s that link to, but fail to activate a receptor on the surface of the cell, such as the metabotropic receptors that are normally bound by glutamate. For example, in the studies described in the following, the effect of denervation of dopamine with 6-OHDA (together with the infusion of TGFa) in a cell migration is apparent. Those knowledgeable about the technique are cap, -ves to direct a cell migration by applying any of the chemical substances described above to an area or objective of the nervous system, particularly given the remarkably clear and accurate images of a patient's brain and spinal cord. that can now be generated, for example, magnetic resonance imaging or computer tomographic exploratory records. Furthermore, it is apparent from the studies described above that altering one or more of the variables associated with the application of a compound that directs migration (these variables include the nature, position, concentration and duration of the application) can be altered to direct more precisely the path of migration that follows the cells and to define the place to which they will come to rest. ? . Factors of Differentiation While some neural precursor cells can spontaneously differentiate given enough time, a substantially greater benefit can be realized by controlling when and where differentiation is carried out, exercising such control allows you to limit the ("repopulation" neural ( which may be partial or complete, as long as it is sufficient to reduce the neurological deficiency), to CNS areas in need thereof In accordance with this, several stimuli may be administered before, during or after contracting the progenitor neural cells with a polypeptide that binds the EGF receptor.In general, the stimuli that induce differentiation can be "general" or "directed." A stimulus of general differentiation is one that stimulates the cell to differentiate itself as it would naturally and is applied in wherever a neurological deficiency can be reduced by stimulating a cell to express its genotype For example, it is known in the art that cells of the subependymal striatal zone differentiate into GABAergic neurons upon exposure to general differentiation signals. Therefore, stimulating these cells to differentiate themselves by applying a general differentiation factor would reduce the neurological deficiencies associated with Huntington's disease.; in these patients, the GABAergic spiny neurons of the medium are selectively lost. Those skilled in the art are able to apply known means to stimulate general differentiation to stimulate the differentiation of the proliferating and migrating cells of the present invention. For example, contacting cells with a retinoblastoma protein is known to cause them to exit their cell cycle, a requirement for differentiation (for the recent study see, Slack et al., J. Cel l Diol. 14 '.: 1 97-1509, 1998) and contacting cells with a cell cycle associated with the kinase inhibitor, p21, can maintain the cells in a post-mitosic (i.e., differentiated) state (Berger et al., Soc. Neurosci. Abstr. 22 ^: 505, 1996). Another stimulus that can be applied to stimulate differentiation in the context of the present method is a cyclin D cell cycle regulator (Ouaghi et al., Soc. Neurosci, Abs tr. 2_2: 1706, 1996). If one would like to stimulate the differentiation of oligodendrocyte precursors, integrins should be applied (see, for example, Buttery et al., Soc. Neurosci, Abs tr. 22: 1723, 1996). It is well known that the neurotrophic factor derived from the brain (BDNF) and retnoic acid (RA), which have abilities to stimulate cell differentiation (see, for example, Ahmed et al., J. Neurosci.15: 5765- 5778, 1995). In the case that neural precursor cells are cultured before directed migration, they must be transplanted to an area of the brain that is capable of influencing their differentiation. For example, a high percentage of transplanted differential neural precursor cells, in neurons, when placed close to the subventricular zone (more than 35%), compared with that transplanted to more lateral sites (in which only 0-8% of the cells differentiated) (Catapano and Macklis, Soc. Neurosci, Abs tr 23: 345, 1997). Similarly, transplanted cerebellar precursors express mammals for hippocampal neurons when transplanning in the hippocampus (Vicario-Abejón et al., J. Neurosci 15: 6351-6363, 1995). Accordingly, a person skilled in the art will appreciate that, as an alternative for bringing the progeny of proliferating neural progenitor cells into contact with a compound that stimulates their differentiation, the invention can be practiced by transplantation of cells in or near a region of the brain. that is capable of directing their differentiation. A stimulus of directed differentiation is that which stimulates a cell to differentiate itself, but with a phenotype that is different from what it would naturally express. A directed differentiation factor will be applied whenever a neurological deficiency can be reduced by stimulating a cell to express its unnatural phenotype. Such an instance occurs in the case of Parkinson's disease, where the differentiation of striatal cells in cells that produce dopamine could replace the loss of the dopaminergic innervation of the substance nigra. Similarly, one would like to hit the target to stimulate the expression of a cholinergic phenotype in the septal region, where cells are selectively lost in Alzheimer's disease; in the spinal motor neurons, which are lost in a lateral amyotrophic sclerosis and after traumatic spinal injuries and in oligodendrocytes, which are lost in demyelination disorders such as multiple sclerosis. Factors of the GDNF / neurturin family (TGFβ), which are derived from a glial cell line, can induce a differentiation in neural cells (which is further enhanced by the RA) (Hishiki et al., Cancer Res. 5P: 2158 -2165), and GDNF stimulates the differentiation of motor neurons in rat ventral mesencephalial cultures. BDNF and ciliary neurotrophic factor (CNTF) '-also promotes the differentiation of motor neurons (it seems that their effects are added to be additive, are not synergistic with the effects of GDNF) (Zurn et al., J. Neurosci Res 44: 133-141, 1996). In addition, the differentiation of motor neurons can be induced by applying vitronectin, which is expressed in the ventral region of the neural tube (Martínez-Morales et al., Devel opmen t 12: 5139-5147) and the protein encoded by the sonic hedgehog ( Tanabe et al., Curr. Biol. 5_: 651-658, 1995). A member of the sonic hedgehog family, the Indian hedgehog, is expressed in the developing and mature retina and promotes the proliferation of retinal progenitors and the development of photoreception (Levine et al., J. Neurosci., 17: 6277- 6288, 1997).

Neural cortical progenitors adopt a phenotype specific to a region influenced by EGF, TGFa, and by the type of substrate in which they grew. EGF, TGFa doubled the percentage of limbic neurons derived from the non-limbic area precursors when they were cultured on Matrigel ™ sheets with deficient growth factor or with collagen IV (Ferri et al., Devel opment t 121: 1151- 1160, 1995). It is known that insulin affects the differentiation of cultures of cells of fetal neurons, even more than IGF-1 (Abboud et al., Soc. Neurosci, Abs tr 23: 1425, 1997). The basic growth factor of the fibroblast (bFGF) and the neutrophins can be used to direct the differentiation of hippocampal cells (Vicario-Abejón et al., Uzuron 15: 105-114, 1995). It is known that insulin affects the differentiation of cultures of neuronal cells of the fetus, even more than IGF-1 (Abboud et al., Soc. Neurosci, Abs tr 23: 1425, 1997). The basic fibroblast growth factor (bFGF) and the neurotrophins can be used to differentiate the hippocampal cells (Vicario-Abejón et al., Neuron 1_5: 105-114, 1995). In one embodiment, the methods of the invention can be applied to restore the neural pathways that had been lost by a degenerative disease. For example, differentiated GABAergic striatal neurons can restore the striatopalidal projections after their differentiation. Those skilled in the art are skilled in recognizing numerous neural pathways that are amenable to reconstruction by the methods of the present invention. F. Pharmaceutical Compositions Polypeptides that are suitable for use in the present invention (ie, those that bind to the EGF receptor or stimulate differentiation, also referred to herein as "active compounds"), can be incorporated into suitable pharmaceutical compositions to be administered . Such compositions specifically include one or more polypeptides and an "acceptable pharmaceutical carrier", a term which is intended to include any or all of the solvents, dispersion media, coatings, antibacterial agents, antifungal agents, isotonic agents and delaying absorption and the like. , that are compatible with the pharmaceutical administration. The use of such media and agents is well known in the art. Except where conventional means or agents are incompatible with the active compound, the use thereof in the compositions is contemplated. Those skilled in the art appreciate the need to formulate pure pharmaceutical compositions for their desired route of administration (parenteral injection, for example intravenous, subcutaneous or intramuscular, oral administration or direct application to the affected area may be included). It is contemplated that in the present methods they will be carried out by applying polypeptides to neural precursors harvested from the brain and cultured or applied directly to the cells in vivo (by, for example, an infusion through an injection or bypass cannula, or by implantation within a carrier, eg, a biodegradable capsule), although other routes of administration, particularly parenteral (preferably intravenous), are also within the scope of the invention. Solutions or suspensions useful in the pharmaceutical compositions of the present invention (for example, in a composition containing a polypeptide that binds to the EGF receptor and to a compound that stimulates the differentiation of precursor neurons), may include: sterile diluents such as water, a normal saline solution, stable oils, polyethylene glycols, glycerin, propylene glycol or other synthetic solvents; antibacterial or antifungal agents such as benzyl alcohol, paraben (for example, methyl paraben), chlorobutanol, phenol, ascorbic acid, thimerosai, and the like; antioxidants such as ascorbic acid or sodium disulrito; watchdog agents such as EDT ?; buffer substances such as acetates, substrates or phosphates; and tonicity or adjustment agents such as sodium chloride or dextrose. The pH can be adjusted with acids or bases, such as hydrochloric acid or sodium hydroxide. Pharmaceutical compositions suitable for injection include sterile aqueous solutions (wherein the active compound is soluble water) or sterile dispersions and powders - for sterile solutions or dispersions injectable extemporaneously. For intravenous administration, suitable carriers include physiological saline, bacteriostatic water, Cremophor EL1"1 (BASF; Parsippany, NJ) or buffered phosphate buffered saline (PBS). In all cases, the composition must be sterile and must be fluid to the extent that there is easy injectability (the proper fluidity can be maintained, for example, by using coatings such as lecithin, maintaining a certain particle size in the case of dispersions and including surfactant). The composition must remain stable under the conditions of manufacture and storage and must be preserved against the contaminating action of microorganisms such as bacteria and fungi, as described above. In several cases, it would be preferable to include isotonic agents, for example, sugars, polyalcohols such as mannitol, sorbitol, sodium chloride in the composition. Prolonged absorption of the injectable compositions can be achieved by including in the composition an agent that delays absorption, for example, aluminum monostearate and gelatin. Sterile injectable solutions can be prepared by incorporating an active compound (eg, a polypeptide that binds the EGF receptor) in the required amount in an appropriate solvent with one or a combination of the ingredients listed above, as required, followed by a filtered sterilization. Generally, dispersions are prepared by incorporating the active compound into a sterile vehicle containing a basic dispersion medium and the other ingredients required those listed above. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum drying and freeze drying, which produces a powder of the active compound plus any additional desired ingredient of a previously filtered sterile solution. In one embodiment, the active compound is prepared with one or more carriers that will protect the compound against rapid elimination from the body, such as a formulation that controls release, including implants and microencapsulated delivery issues. Biocompatible biodegradable polymers can be used, such as vinyl ethylene acetate, polyanhydrides, polyglycolic acid, collagen, polyorthoesters, and polylactic acid. Methods for preparing such formulations will become apparent to those skilled in the art. The materials can also be obtained commercially, for example, from Alza Corporation and from Nova Pharmaceuticals, Inc. Suspensions of liposomes can also be used as pharmaceutically acceptable carriers. These can be prepared according to methods known to those skilled in the art, for example, as described in the North American Patent. Mo. 4,522,811. It is especially advantageous to formulate the compositions of the invention in unit dosage form for ease of administration and uniformity of dosage. The unit dosage form, as used herein, refers to discrete physical units disposed in unit dosages for the subject to be treated; each unit contains a predetermined amount of an active compound, calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. The specification for the unit dosage forms of the invention are dictated by and depending directly on the unique characteristics of the active compound, the particular therapeutic effect to be achieved and the inherent limitations of the composition technique, such as an active compound for the treatment of individuals. Instead of the direct application of polypeptides that bind the EGF receptor or stimulate cell differentiation, nucleic acid molecules encoding those polypeptides can be inserted into vectors and used as vector gene therapy. Vector gene therapy can be applied to a subject by, for example, an intravenous injection, local administration (US Pat. No. 5,328,470) or by a stereotactic injection (see, eg, Chen et al., Proc. Na ti. Acad. Sc. USA 9_1_: 3054-3057, 1994). The pharmaceutical preparation of vector gene therapy may include gene vector therapy in an acceptable diluent, or may include a slow release matrix in which the gene delivery vehicle is embedded, for example, in the brain or in the spinal cord. Alternatively, where the complete gene delivery vector can be produced intact from recombinant cells, e.g., retroviral vectors, the pharmaceutical preparation can include one or more cells that produce the gene delivery system. The pharmaceutical compositions can be included in a container, package or dispenser together with instructions for administration. G. Treatment regimens By way of example (those skilled in the art are able to extrapolate from one model (either from an in vitro or one in vivo model) to another, which progresses towards optimal dosages for human patients) , for a rodent brain, the infusions to stimulate the proliferation of the neural precursor cells was continued for a period of at least two weeks. The result was a marked increase in the numbers of undifferentiated progenitor cells along the adjacent ventricle. The continuous infusion of TGFa applied in the working examples in the following also supports radial cell migration, but is not sufficient by itself, to stimulate the massive radial migration observed in certain animals. The duration of any treatment carried out according to the methods described herein may vary with the desired results. For example, in the examples of work in the following, the cells greatly increased their number for more than a week before their mass migration away from the ventricle. In addition, the delay of migration is facilitated by denervation of the target region, either neurochemically or mechanically and can be facilitated pharmacologically by the concurrence of the factor or infusion factors, such as another neurotrophic factor, TGFβ, which increases expression of the cell adhesion molecules that are believed to underlie radial migration (as described above). The migration pattern and the final location of the crest of migratory cells can be controlled by altering the location of the infusion. Those skilled in the art are able to determine the required dosage of a compound administered in the context of the present invention. Preferably, the dosage should fluctuate, whether infused or released from a durable release vesicle between 1 and 100 ng / kg / day of an active compound or ingredient (e.g., TGFa or any of the factors described below). previous); more preferably, between 1 and 50 ng / kg / day; and more preferably should be administered between 1 and 10 ng / kg / day. EXAMPLES Example 1: Expression of TGFα and EGF Receptor RNAs in Normal Development in the Adult Nigrostriatal System As reviewed in the detailed description, mRNAs encoding the neurotrophic factors of the EGF family are highly regulated in the nigrostriatal system. In the studies described in the following, the expression of the mRNAs of the TGFa and EGF receptors is examined in normal development and in the adult system of rodents. A. Preparation of Animals and Tissues An adult male rat and a female that was taken gestation time (250-350 g) were obtained from Simonsen (Gilroy, CA), for these experiments and all others described in the present, the animals were kept in a nursery with controlled temperature and humidity. The use of animals for all previous experimental procedures was approved by the research committee ..nimal from the University of California, Irvina, according to the National Institute of Health Guidelines. The newborn (PO) animals, those that were one day old (PI) and the P4 animals were anesthetized by unwarranted hypothermia by decapitation. PÍO, P21, and the adult animals were sacrificed by decapitation. Their brains were quickly removed, frozen in isopentane at -20 ° C and stored at -70 ° C. Cryostatic coronal sections were cut at 20 μm and adhered by melting onto slides covered with VectabondTw (Vector Labs, Inc.), which were arranged in rows in order from previous to posterior. The sections were post-looped with 4% formaldehyde in 0.1 M phosphate buffer (pH 7.4) for 1 hour, rinsed in a phosphate buffer and air-dried. The sections were stored with a desiccant at -20 ° C until they were processed. B: Hybridization Probes The TGFα mRNA probes were generated from a fragment of a cDNA notide number 550 Xbal / BamHI from the final 5 'of TGFα rats and subcloned into pGEM 7Zf) Pro-mega, Inc.). Sensitivity and antisense probes were transcribed with SP6 and T7 polymerases, respectively. The rat EGF receptor mRNA probes were produced from the insert of a 718 BamHI / Sphl base pair of the 5 'end of the gene, in pGEM 7Zf. Probes for TH rats were created using the 1.2 kb BamHI / EcoRI fragment, subcloned in pGEm 7Zf. Antisense subclones for the ERGF receptor and for TH were transcribed with T7 polymerase. Antisense subclones for the EGF receptor and for TH were transcribed with T7 polymerase. The sense subclones for the EGF receptor and where TH were transcribed '-on the SP6 polymerase. All probes were radiolabelled by transcription in the presence of [35 S] UTP (NEN Research Products, Inc.). C. Hybridization and in situ analysis Hybridization of the nic acid in situ was carried out according to the method described by Simmons in al. (J. Histotech 12: 1169-181, 1989) except that the developing brains were treated with a solution of proteinase K at 0.0001% and with 0.05 M EDTA. The sections were incubated overnight at 65 ° C with sensitivity or antisense probes at a concentration of 107 cpm / l. Adjacent sections of the same animals were hybridized in each of the probes so that direct comparisons of their anatomical distribution could be made. The slides of the developing and adult animals were grouped together and a designated brain paste designated "C" was applied to a Betamax autoradiographic hyperfilm (Amersham, Inc.) for six to seven days. After the successful autoradiography film, the slides were immersed in a Kodak NTB-2 emulsion and exposed for four weeks.The autoradiographic film sheet and the NTB-2 emulsion were developed with the D-19 developer and with the Papid Fix ( Kodak, Inc.). The sections of the brain were then counterstained with thiamine and discarded. Submerged and stained sections were examined semiquantitatively and photographed by illuminated and dark field microscopy. The expression of the mRNAs of the TGFa receptors and EGF in the nigrostriatal system was plotted following selected points in time from early postnatal development to adulthood. Hybridization of TGFa mRNA in the early postnatal striatum was found in abundance but was gradually reduced when approaching adult levels by P21. Expression in the corpus callosum increased through postnatal development to levels comparable to those of the striatum. The mRNA of TGFα was not detected with significant abundance in the developing or adult substance nigra. The striatal mRNA of the EGF receptor reaches its maximum levels soon during post natal development and decreases again around P21. The EGF receptor was higher in the neuroepithelial surroundings of the lateral ventricles, but was also found at moderate levels in the striatum body. In the developing ventral midbrain, the EGF receptor mRNA was scarcely detectable in early postnatal brains, but gradually increased to moderate levels by P21. In adult animals, the expression of mRNA of TGFa was moderate in the striatum and less than moderate in the ventral striatum and acoustic nuclei. Hybridization of the EGF receptor mRNA was found at low levels in the striatum body and in acoustic nuclei with a higher dotted expression scattered throughout the entire area. It persisted at moderate levels in the regions of the striatum that immediately surround the lateral ventricles.

In the adult ventral midbrain, hybridization of the EGF receptor mRNA was found in the substantia nigra (SN) particularly in the medial compact part and in the paranigral and parabranchial nuclei of the ventral tegmental area (VTA). Previous studies indicated that the mRNA of the TGFa and EGF receptors are tightly regulated during the ontogeny of the nigrostriatal system and that its expression in the adult 'widely represents the continuation of the developmental pattern (Lazar and Blum, J. Neurosci., 12: 1688- 1697, 1992; Weickert and Blum, Devel. Bra in Res. _86: 203-216, 1995). The hybridization of the mRNA of TGFα and EGF receptors in developing animals and adults almost parallels the findings of these early reports. The persistence of its expression in the adult striatum and in the midbrain is consistent with a supporting role in the mature nigrostriatal system. Moderate expression of EGF receptor mRNA in the adult subependymal regions along the lateral ventricles of the forebrain suggests a role in the maintenance or functioning of the cells of this region as well (Seroogy et al., Bra in Res. 670 : 157-164, 1995; Weickert and Blum, 1995, supra). It has been shown that TGFa (or EGF), supports the survival and differentiation of cells "responsive to EGF" of this region, which are explanted and cultured in vi tro (Reynolds and Weiss, Science 255: 1707-1710, 1992; Reynolds et al. , J. Neurosci. _12: 4565-4574, 1992). It can then carry out similar fuiv ions in vivo during development. EXAMPLE 2: Modulation of TGFα and EGF mRNA expression through the 6-hydroxydopamine lesion and with the striatal infusion of TGFα Hybridization in si tu was used to determine whether the mRNA of the TGFα or nigrostriatal EGF receptors were altered with intrastriatal infusion of TGFα. Additionally, the influence of unilateral 6-OHDA lesions on the expression of receptors in infused and non-infused animals was examined. A. Treatment Groups Adult male Sprague-Dawley rats weighing 250-300 grams were purchased with Simonsen (Girlroy, CA) and assigned to one of five treatment groups: (1) striatal infusion of TGFα, nigral lesion with 6 -HDA (hereinafter, "injury"); (2) infusion with TGFa, without injury; (3) artificial cerebrospinal infusion (aCSF), injury; (4) aCSF infusion without injury; (5) without infusion, without injury. Four to eight animals were used per experimental group. The animals were monitored after each surgical procedure until they were fully recovered and kept at all times in a nursery with controlled temperature and humidity. B. Lesions with 6-hydroxydopamine Rats were anesthetized with 8 mg of xylazine and with 100 gm of ketamine per kilogram of body weight. A cold solution of 4.8 mg / ml 6-hydroxydopamine HCl (ü-OHDA; Sigma Chemical Co.) in 0.9% saline solution with 0.01o ascorbic acid was prepared immediately after injection. Using a sterile technique, a volume of 8 μl was injected stereotactically in the left part of the substance nigra (+3.7 A / P; +2.1 M / L; +2.0 D / V) in a range of lμl / minute using an interaural of zer? as reference (Paxinos and Watson, The Rat Brain in Stereotaxic Coordinates, Academic Press, San Diego, 1986). The success and degree of 6-OHDA lesions were monitored by in-situ hybridization of tyrosine hydroxylase (TH) mRNA in the midbrain. TH is the enzyme that limits the range of synthetic dopamine pathways and is a common marker for neurons that produce dopamine. An animal with an incomplete lesion (which retains significant numbers of nigral TH-IR cells) was excluded from the study and is not included in the total number of animals. C: Infusions osmotic minipumps (model 2002, Alzet, Inc.) were implanted four or five weeks after the injury. The minipumps were filled with approximately 200μl of either 0.05 μg / ml TGFa in an artificial cerebrospinal fluid (aCSF) for the experimental animals, • with aCSF only for the control animals concealed uring the night at 37 ° C before being implanted. After anesthesia, as indicated above and under sterile conditions, the 5-mm cannula fixed to the minibomba (infusion package for the brain, Alzet, Inc.) was stereotactically implanted in the left caudate putamen (+1.2 A / P; + 2. / M / LJ using Breg a as reference (Paxinos and Watson, 1986, supra) and fixed to the skull with carboxylate cement (Figure 1). The minipump itself was placed subcutaneously in an interscapular region. The infusion was released directly into the striatum for a period of two weeks with an inflow of 0.5 μl / hour. D ^ Tissue Preparation At the end of the infusion period, the animals were sacrificed by decapitation. Their brains were quickly removed, frozen in isopentane at -20 ° C and stored at -70 ° C. Cryostatic coronal sections were cut at 20μm and adhered by melting onto Vectabond ™ covered slides (Vector Labs, Inc.), arranged in rows from anterior to posterior. The sections were then fixed with 4% paraformalchlohide in 0.1 M phosphate buffer (pH 7.4) for one hour, rinsed in a phosphate buffer and air dried. The sections were stored with a desiccant at -20 ° C until they were processed. E. Hybridization Probes The TGFα mRNA probes were generated from a 550 Xbal / BanHI nucleotide fragment of the 5 'end cDNA of a rat TGFα subcloned in pGEM 7Zf (Promega, Inc.). Antisense and sensitivity probes were transcribed with SP6 and T7 polymerases, respectively. The rat EGF receptor mRNA probes were produced from a base pair number 718 BanHI / Sphl, from the end '> 'of the gene in pGEM 7Zf. The probes for the TH rats were created using the 1.2 kb BanHI / EcoRI fragment subcloned in pGEM 7Zf. The antisense subclones for the EGF receptor and the TH were transcribed with the T7 polymer. The sense subclones for the EGF receptor and the TH were transcribed with the SP6 polymerase. All probes were radiolabeled by transcription in the presence of [? s] UTP (NEN Research Products, Inc.). F. Hybridization In si tu Hybridization in si tu of the nucleic acid was carried out according to the method described by Simmons et al. 1989, supra). Parallel sections of the experimental and control animals were hybridized overnight at 65 ° C with sensitivity and antisense probes at a concentration of 107 cpm / ml. Adjacent sections of the same animals were hybridized in each of the waves so that direct comparison could be made between their anatomical distributions. The slides of the experimental and control animals were pooled together and a 1C brain allocation according to the standards was applied to a Betamax ™ autoradiographic hyperpelicula (Amersham, Inc.) from three to seven days. After the successful development of the autoradiographic film, the slides were immersed in an emulsion of Kodak NTB-2 and exposed for four weeks. The autoradiographic film sheet and the NTB-2 emulsion were developed with a D-19 developer and Rapid Fix (Kodak, Inc.). The sections of the brain were then counterstained with thiamine and slipped caps were placed. G. Analysis and Quantification The stained and submerged sections were examined and photographed with illuminated and dark field microscopy. The autoradiograms were analyzed quantitatively using an MCID (Microcomputer Imaging Device, Imaging Research, Inc.) system. Samples were taken at multiple sites from the densimetry readings within each anatomical region of interest and were averaged. The relative concentrations of the TGFα and EGF receptor hybridization were then stimulated using a standard computer generated third-degree polynomial curve constructed from the guidelines for brain || C pulp. The estimated values for each region in each treatment group were then averaged and their standard errors were calculated. The regions of the brain ipsilateral to the experimental treatments were compared with the corresponding contralateral regions in the same sections or with the corresponding regions in the control brains in approximately the same positions. The significance of the comparisons was determined using the Student's t-test. H. Normal Expression and Infusion Control Expression of TH-receptor mRNAs, TGFa and EGF in the striatum, the subependymal striatal region and in the SN in the control animals receiving striatal infusions of aCSF, was indistinguishable from that of normal animals (see example 1 for normal development and expression in adults). ). Hybridization of TH mRNA was prominent through SN-VTA. The mRNA of TGFα was not detected in the SN. The EGF receptor mRNA, however, was prominent in the compact part of the medial nigra substance (SNc), and in the paranigral, parabranchial and interpeduncular nuclei of the VTA (Figure 2). Hybridization of the mRNA of TGFa was manifested in the caudate putamen and in the acoustic nuclei (NA), being slightly less dense in the NA. Hybridization of the EGF receptor was found at low levels throughout the body of the striatum and the NA with higher punctuated expression dispersed through the anteterum of low levels and at moderate levels in the proliferative regions of the striatum surrounding the lateral ventricles. I. Effects of 6-OHDA lesions Unilateral nigral lesions with 6-OHDA reduced hybridization of TGFα mRNA to the ipsilateral striatum by 25%, but had no effect on the hybridization of TGFα mRNA in the contralateral part (Figure 5). ). Hybridization of the striatal and subependymary EGF receptor remained unchanged in the injured animals shared with normal animals (Figure 6). In the midbrain, lesions with 6-OHDA abolished the hybridization of the EGF receptor in the ipsilateral SN-VTA. J. Effects of Infusions of TGFα In uninjured animals receiving infusions of TGFα, the hybridization of TGFα mRNA to the infused striatum remained unchanged compared to contralateral striatum or the striatum of normal animals (Figure 5). A few of the animals that received infusions of either TGFα or aCSF showed a slight increase in the hybridization of TGFα mRNA immediately around the "infusion cannula scar." Hybridization of TGFα mRNA in the substantia nigra did not increase with the infusions to detectable levels Hybridization of the EGF receptor mRNA increased markedly in the ipsilateral subependymaric region, but not in the rest of the estriatumn in all the animals that received infusions of TGFα (Figure 6). the normal was observed in the hybridization of the EGF receptor in the SNc with the infusions of TGFa alone K. Infusion TGFa and injury with 6-OHDA combined The hybridization of the striatal TGFa mRNA in animals that received both striatal infusions of TGFa and subsequent lesions nigrals with 6-OHDA was indistinguishable from animals that had lesions only (Figure 5). n EGF receptor in the midbrain of animals infused with TGFa / lesioned 6-OHDA was indistinguishable from that of the injured animals only. Hybridization of the EGF receptor mRNA in the forebrain revealed a normal crest of dense hybridization in the ipsilateral striatum body in addition to increased hybridization in the subependymarian region (Figures 4.6 and 7). The ridge was found in five of the six rats in the group that combined the infusion with TGFα and the lesion, but only in one of the six rats in the group with infusion of TGFα and without injury. Hybridization of the EGF receptor in the vicinity of the striatum did not change.

L. Discussion The results described in the above allow an analysis of the modulatory effects of nigral lesions with .6-OHDA or infusions of TGFα, or both, the expression of the mRNAs encoding the TGFα receptors and the EGF in the striatal systems of adult rodents. The results clearly showed changes in expression associated with each treatment individually and a unique pattern of striatal expression when the two treatments were combined. 1. Effects of Lesions with 6-OHDA Lesions of the midbrain with 6-OHDA reduced the hybridization of TGFα mRNA in the striatum at 25 ?. to several weeks after the injury. If TGFα peptide levels are parallel in their expression to TGFα mRNA in this system the decrease in mRNA of TGFα may be an aspect of the lesion of the rodent model that is not similar to the human idiopathic PD: TGFα increased markedly in the striatum of PD patients (Mogi et al., Neurosci, Let t 180: 147-150, 1994). It has been shown that TGFa improves a number of the measurement of the functions of the dopamine neuron in vitro (Alexi and Hefti, Neurosci 55: 903-918, 1993). The increase of TGFa (and of EGF and other trophic factors) may therefore reflect a response to the continuous "degeneration of dopamine neurons and their striatal efferents and may contribute to the staying capacity of dopamine cells in the midbrain to compensate for the loss of striatal dopaminergic innervation (Mogi et al., 1994, supra) .Therefore, a model with a partial - or perhaps chronic - wound may better represent this aspect of human PD. The timing of the loss of dopamine cells may also help to explain the apparent discrepancy between the rodent 6-OHDA model and the human PD.In the rat model, the dopamine neurons of the midbrain are relatively rapidly determined by a single neurotoxin injection The chronic, progressive degeneration of dopamine neurons of the mesencephalon in human PD occurs for several years. The animals were sacrificed long before the midbrain dopamine cells had degenerated. There may have been early changes in the expression of striatal TGFα mRNA in these animals that did not appear in our experiments. It will be of interest to determine how the expression of mRNA in TGFα varies in the rat model in short periods after injury, while dopamine neurons are in the process of degenerating. The moderate expression of TGFa mRNA in the caudate putamen is consistent with its putative role as a growth factor derived from the target for dopamine neurovirals of the midbrain. The fundamental cause of this decrease in ipsilateral striatum after a neurotoxic injury in the midbrain is unclear. It has been shown that the dopamine receptor binding influences the expression of TGFa mRNA in the hypothalamus (Borgundvaag et al., Endocrinol 130: 3453-3458, 1992), but no interaction of this type has yet been demonstrated in the estriatum. The mRNA of TGFa is expressed in subpopulations of neurons and glia in the normal adult striatum of rodents (Seroogy et al., J. Neurochem. ^ 60: 1777-1782, 1993). The denervation of dopamine from the stratium could potentially have influenced the mRNA expression of r, '< - 7u. in postsynaptic neurons, astrocytes, or both. The contralateral stratial expression of the mRNA of TGFa was not significantly altered by the 6-OHDA lesion. This finding is also consistent with the decrease in the expression of TGFa mRNA due to the mediated denervation of dopamine. Only a small percentage of the mesostriatal dopaminergic projections are contralateral (Loughlin and Fallon, Neurosci, Lett 32_: 11-16, 1982), therefore it is expected that any of the contralateral regulatory effects resulting from an injury will be minor in comparison with ipsilateral effects Hybridization of the EGF receptor mRNA _n the denervated striatum-DA does not differ significantly from the contralateral CP or from the untreated control striatum. Again, there may have been early changes <-n expression due to midbrain injury or implantation of the infusion cannula that did not become apparent several weeks after the injury or two weeks after implantation. The abolition of the hybridization of the EGF receptor mRNA in injured SNc confirms a similar observation after a 6-OHDA lesion of the medial of the anterior brain bundle (Seroogy et al., Neuroreport _6: 105-108, 1994). This decrement induced by the lesion was previously cited as evidence of the expression of the EGF receptor by the nigral dopamine neurons (Seroogy et al., 1994, supra), but the possibility remains that the production of the glia EGF receptor mRNA nigrai is subject to be regulated by the wound or death of nearby nigral neurons. Interestingly, the receptor binding of EGF in the mid-postmortem brains of PD patients remains unchanged compared to normal brains (Villares et al., Brain Res. 628: 72-76, 1993). Therefore, the loss of EGF receptor mRNA expression after injury represents another difference between the injured model rodent and a human PD. As well as the expression of TGFa in the striatum, a partial lesion in the model can mimic better in a rat brain the changes observed in a human brain than Parkinson's disease. 2. Effects of Infusions of TGFα In unharmed animals, the infusion of TGFα or aCSF does not significantly alter the hybridization of the APIlm of TGFα from its normal levels in the mid-brain striatum. Despite reports of self-stimulated TGFα expression in other tissues or cell types (Coffey et al., Na ture 328: 817-820, 1987; Barnard et al., J. Biol. Chem. 269: 22817-22822 , 1994), the results of the present study do not provide evidence for such activity in this system. The self-stimulatory effects in whose previous studies occurred only for a few hours. The brain tissue in the present study was obtained after continuous exposure to the growth factor for a period of two weeks. Therefore, early regulation will not be evident near the beginning of the infusion and then down. As in transcripts of TGFα and EGF receptors in animals with only lesions, it would be of interest to examine the time course of modulation at several early times before the start of experimental treatment. The slight increase in mRNA of TGFα observed in some animals immediately around the scar tissue of the infusion was found in the striatum both infused with TGFα and those infused with aCSF. Therefore, it is likely that it can be attributed to the continued mechanical wound and to the gliosis caused by the cannula itself and not to the infusion. Infusions of TGFα increased the hybridization of EGF receptor mRNA in the ipsilateral subdymal region but not in the rest of the striatum. In other tissues, the mRNA of the EGF receptor can be modulated by various chemical or mechanical means. The EGF peptide increased the EGF receptor mRNA in numerous types of mammalian cells in vi tro (Earp et al., J. Biol Chem. 261: 4777-4780, 1986; Kesavan et al., Oncogene 5: 483-488, 1990) . Retinoic acid caused a similar increase in the normal fibroblasts of rodents (Thompson and Rosner, J. Biol. Chem. 264: 3230-3234, 1989) and in a row of transformed cells of the rat (Raymond et al., Cell Growth Diff. 1: 393-399, 1990). Exposure to cyclohexamide, by itself or by EGF, stimulated an increase in human cultures of cytotrophoblasts, and stabilized transcripts of the EGF receptor, thus providing another mechanism that improved transcription to increase the total abundance of the EGF receptor mRNA (Kesavan et al., 1990, supra). Transection of the sciatic nerve in the rats resulted in a graduated increase of the EGF receptor mRNA at the most damaged ends (Toma et al., J. Neurosci. 12: 2504-2515, 1992). Protamine treatment increased the JI-EGF-binding and the number of cell receptors on the surface in mouse and human cell lines in vi tro (Lokeshwar et al., J. Biol. Chem. 264: 19318-19326, 1989) . TGFa can mimic these actions and increase the production and / or longevity of copies of the EGF receptor in existing subependymal cells. It can also stimulate transcription in cells that do not normally express appreciable amounts of EGF receptor mRNA. Both effects can be easily investigated further in vivo with technical routines known to those skilled in the art. A further possibility is that TGFa is stimulating the proliferation of subependymal cells and increasing the total number of cells expressing mRNA of the EGF receptor. EGF and TGFα are potent mitogens for cultures of "EGF responding" cells, explanted from the subependymal region (Reynolds and Weiss, 1992, Science 255: 1707-1710). The strong striatal inductive effect that the infusion of TGFa has on the hybridization of the APNm of the EGF receptor in the subependymal can indicate that the proliferating cells in the intact brain respond similarly to the cells in vivo. 3. Combination of infusion of TGFα and Lesion 6-OHDA In animals that received the combination of lesions and infusions of TGFα, the hybridization of striatal TGFα mRNA was indistinguishable from that of the animals that received the combination of lesions and infusions. aCSF. Although TGFα has a potent auto-stimulatory effect in other tissues, it did not significantly alter the reduction of striatal TGFα mRNA hybridization in the present study. The loss by means of 6-OHDA of the mesencephalic EGF receptor mRNA also remained unaffected by the infusion of TGFα. In the latter case, weeks before the infusion began, the middle brain lesions were carried out and the dot cells were destroyed. "Therefore, the growth factor had not had an opportunity to prevent its elimination. There is some evidence that the dopamine cells themselves express the mRNA of the EGF receptor (Seroogy et al., 1994, supra) and that TGFa can moderate the loss.; \ c the markers in the strialtal dopaminergic innervation .ji is co-administered with the neurotoxin. Therefore, the time interval between the neurotoxin lesions and the administration of TGFα may explain why infusions of TGFα have no impact on the abolition of mRNA from the middle brain EGF receptor. In human brains suffering from Parkinson's disease, the mesencephalic EGF receptor binding remains unchanged compared to normal brains (Villares et al., 1993, supra). The enormous increase in striatal TGFα (and in other neurotrophic factors) with PD (Mogi et al., 1994, supra) may mask a reduction in the number of dopamine cells that express the EGF receptor, increasing expression levels in the neurons that remain. On the other hand, in vitro experiments suggest that several of the trophic effects of TGFα on mesencephalic dopamine neurons are mediated, at least partially, by the glia (Alexia and Hefti, 1993, supra). Therefore TGFa can act in paracrine mode (direct) and sequential (indirect) mode of transport to influence dopamine neurons. The hybridization pattern of the EGF receptor mRNA in the subependymal zone of animals injured with TGFα was similar to that observed in animals not injured with TGFα. The most outstanding characteristic in the ipsilateral stratium of these animals was a dense hybridization crest quite outside the body of the striatum, even more intense than the improved hybridization in the subependymal zone. The ridges do not correspond to any known anatomical feature and were not evident with the TGFa or TH probes. Hybridization of the EGF receptor mRNA in the striatum without crest was the same as in the striatum of all other groups.

The neurotoxic damage by the 6-OHDA lesions ends and the mechanical injury by implantation of the infusion cannula may have stimulated the proliferation and activation of the gual cells. Previous studies have shown that there is gliosis and an increase in the expression of the astrocytic EGF receptor as a result of an injury (Nieto-Sampedro et al., Neurosci, Lett 91: 276-282, 1988, Fernaud-Espinoza et al., Glia 8: 277-291, 1993). In addition, TGFa may play a role in the reactivity of astrocytes (Junier et al., J. Neurosci, 14: 4206-4216, 1994). Another possibility is that the proliferative cells of the subependymal region were removed from the ventricle and attracted to the overlying striatum by the combination of infusion of the growth factor and the middle brain lesion. TGFa is a potent chemoattractant of various cell types (P.eneker et al., Development 121: 1669-1680, 1995), but by itself it was not sufficient in most animals to stimulate ridge formation. The formation of the cellular crest may have been facilitated by the lesions of the midbrain. The origin and identity of these cells will be examined in the following example. Example 3: Striatal Crest Characterization As described above, the striatal infusions of TGFα when combined with the nigral lesions of 6-OHDA induce the formation of a dense crest of cells in the striatum body that they express abundantly the EGF receptor mRNA, but no more TGFa in the surrounding tissue. The ridge was composed of a mass of densely packed cells, facilitating their clear detection using simply thionine staining. The identity of the anomalous striatal ridge was not apparent, but three possibilities were considered. Gliosis in response to injury is a characteristic of both traumatic and neurotoxic size in brain tissue. Typically, both types of lesions in the brain stimulate astrocytosis and the infiltration of astrocytes and glia into the injured tissue (Fernaud-Espinoza et al., Gl ia 8: 211-291, 1993). It has been shown that astrocytes ~ express immunoreactivity to the EGF receptor, particularly as a response to a brain injury (Gomez-Pimilla et al., Bra in Res. 438: 385-390, 1988; Nieto-Sampedro et al., Neurosci. Lett 91: 276-282, 1988). In addition, TGF itself stimulates the proliferation of estrocites (Alexi and Hefti, Neurosci 55: 903-918, 1993). Therefore, the possibility that the striatal ridge was a mass of cells that respond to the combination of mechanical and neurotoxic damage and infusion of the growth factor was considered. A second potential source for the ridge was investigated that was related to the different anatomy of the striatum of rodents. The ridge does not correspond to any anatomical feature previously identified. In rodents, caudate and putamen are not distinct anatomical structures. No anatomical or neurochemical marker has been identified so far that distinguishes in these two nuclei of the basal ganglia in rodents. However, during prenatal and early postnatal development, the neurogenetic gradients in different regions of the developmental striatum correspond to characteristic gradients in the caudate and putamen in animals in which these nuclei are anatomically discrete (Bayer, Intl. J Devel. Neurosci.2_: 163-175, 1984). In rodents, new striatal neurons rostral to the junction of the anterior commissure were added in a lateral to medial gradient in such a way that the last neurons born are those closest to the lateral ventricle. The same pattern is observed in the development of the caudate nucleus, suggesting that the anterior striatum in rodents is more a "caudate-like" region. From the caudal to the junction with the anterior commissure, neurons are added in a medial to lateral gradient, similar to the development of putamen in animals in which it is anatomically different. Therefore, the posterior striatum of rodents may be more "putamen-like". We consider the possibility that the striatal crest could then represent a previously unknown edge between these two regions of the striatum of the rat that allowed a dense cell construction, perhaps due to some neurochemical difference. A third possibility for the source of the striatal ridge was also examined. It was found that explanted cells from the subependymal areas of the lateral ventricles of the forebrain of adult mammals were able to proliferate and differentiate into new neurons and glia, particularly when cultured in the presence of neurotrophic factors of the EGF family, including the TGFa (Reynolds et al., J. Neurosci. 12_: 4565-4574, 1992; Morshead et al. , Neuron 13: 1071-1082, 1994). Recently, the EGF or TGFa axis infused into the lateral ventricle stimulated the proliferation of "the EGF response" of the progenitor neural cells and of the rods in the mouse adult brain (Craig et al., J. Neurosci. : 2649-2658, 1996). One possibility for the source of the striatal ridges in the present studies was that the TGFa infusions stimulated a similar proliferative activity in the brains of the rats. Additionally, the possibility that the striatal crests were mass migrations of proliferating neural progenitor cells derived from the subependymal regions was considered. The experiments described in the following serve to characterize these anomalous striatal ridges using a variety of istochemical = and imunohistochemical techniques. The origin of the crest and the factors that influence its appearance were also investigated by examining the time course of its formation in the striatum and altering the combinations of surgical and chemical treatments. A. Experimental Protocols Adult male Sprague-Dawley rats weighing between 250-300 grams were used throughout the study. Twenty-four animals received normal mydriatriatal infusions of rat TGFα (0.5 μg / day, Sigma Chemical Co.). Another 26 rats received either artificial cerebrospinal fluid (aCSF) or no infusion. A subgroup of animals in the normal TGFa infusion group and in the control group received stereotaxic injections of 6-OHDA into the substantia nigra 48 hours after the infusions began. The animals used in this part of the study were classified into six groups according to their infusion-injury combination, as follows: Infusion of TGFa, lesion (n = 13); infusion of TGFα, without injury (n = ll); infusion of aCSF lesion (n = 12); infusion of aCSF, without injury (n = 9); no infusion, injury (n = l) without infusion without injury (n = 4). Additional animals received infusions of TGFα in other regions of striatum, lateral ventricle, cerebral cortex or septum. Four more animals (two per group) received infusions of midastratal TGFα in half or one tenth of the normal dose. Also, two animals received midestriatal infusions of the epidermal growth factor (EGF) in place of TGFa. The EGF administered in these rats was at the normal dose of 0.5 μg / day. All the animals in these extra groups were injured. The rats in all the experiments were perfused typically from one to 16 days after the injury (3-18 days of infusion). To determine if the crest would persist after the infusions had stopped, the minipumps were removed from four animals with infusions of TGFa at the end of two weeks, but these animals were not perfused until several days later. The brain sections were prepared and stained using various immunocytochemical and hiatochemical techniques. B. Infusion of TGFα The rats were anesthetized with 8 mg of xylazine and 100 mg of ketamine / kg. Infusions of TGFa were provided for 18 days through an Alzet osmotic mini pump (2002). The minipumps were filled to about 200μl with either aCSF for the control animals or with 20μg TGFa in 400μl of aCSF (50μg / ml) for the experimental animals. Under sterile conditions, the infusion cannula was placed in a stereotaxic coordinate (+1.2? / P; + 2.7 M / L; -6.0 D / V) based on Bregma (Paxinos and Watson, the Rat Brain in Stereotaxic Coordinates, Acaclemic Press , San Diego, 1986) and stuck to the top of the skull with dental cement. The infusion was released through the cannula at approximately 0.5 μl / hours. Some other control animals received infusions either in the lateral ventricle, the cerebral superior cortex or in other areas. C. Neurotoxic injury Forty-eight hours after the minipump was implanted, the rats were anesthetized as above. 4.8 mg / ml of a very cold solution of 6-OHDA HCL, was prepared immediately before the injection. Using a sterile technique, the neurotoxin was injected stereotaxically into the ipsilateral nigra substance (+3.7 A / P; +2.1 M / L; +2.0 D / V) using the interaural zero as a reference (Paxinos and Watson, 1986, supra). A volume of 6-8 μl was injected at a graduation of 1 μl / minute. D. Tissue Preparation The animals were perfused with 500 ml to 4% paraformaldehyde in 0.1 M phosphate buffered saline (PBS, pH 7.4) from one to 16 days after the lesion and their brains were placed in sachase twenty%. The next day, the brains were frozen in isopentate at -20 ° C. Then they were cut from forty micras in a microtome frozen in 2% paraformaldehyde in 0.1 M PBS. Continuous sections were taken through the striatum and the nigra-VTA substance. Representative sections were taken through the rest of the brain. E ^ Missi dyeing For the Nissl dyeing, microtomated brain sections were mounted on gelatin-covered slides and allowed to dry overnight. They were then dehydrated and rehydrated with an ethanol bath and placed in a thionin solution for approximately four minutes. The sections were dehydrated through a series of ethanol baths, purified with successive washes of Histopurifier and covered with sliding covers. The sections were viewed under a light microscope and photographed with Pan technical film (Kodak, Inc.) at 100 ISO ISO-110 processed for six minutes). F. Silver Dyeing The fibers and degenerative cells of the crest were marked using a modification to the Nauta dyeing method, similar to procedure I of Fink-Heimer (Giolli and Karamanlidis, in: Neuroanatomical Rt search Techniques, RT Robertson, Ed. , pp. 211-240, Academic Press, New York, 1978). Briefly, sections that floated freely were placed in 0.05% potassium permenganate before treatment with a fresh mixture of 1% hydroquinone and 1% oxalic acid. They were then treated successively with solutions of uranyl nitrate / or silver nitrate in increasing concentrations. After further rinsing, the sections were reacted on an ammoniacal silver substance, then in an ethanol / citric acid / reducing paraformaldehyde and finally sodium entiospiphate. After dyeing, the sections were mounted on glass slides and allowed to dry on a drying slide for 15 minutes. The sections were then dehydrated through successive washes with ethanol with concentrations that were increased, degreased in three successive washes Histopurificadores and covered with sliding covers. G. Immunoisotoxicity The quality and extent of the nigral lesion was determined by the loss of TH-IR in the ipsilateral ventral midbrain. Antibodies against the acid fibrilose grail protein (GFAP), a marker for astrocytes, nestin, a marker for neural progenitor cells and vimentin, a marker for radial dual cells were used in the neurochemical characterization of the crest. Immunosto-chemistry was carried out in sections that floated freely. Briefly, sections of the brain were washed in 0.1 M PBS or Tris buffer. (TBS; 3 x 10 minutes) were then incubated for 1 hour in an obstructing solution consisting of 3% normal 3% goat serum in 0.1 M PBS with 250 μl Triton X-100. Then, they were incubated overnight in a temperature-controlled room on a rotator with an antibody solution diluted in obstructing solution: rabbit antiserum TH (1: 500, Eugene Tech Intl., Inc.), anti-GFAP ( 1: 6400; Dako Corp.), mouse anti-mouse vimentin (1:50, Sigma Chemical Co.), or mouse anti-nestin supernatant (1:20, University of Iowa Hybridoma Bank). sections were washed and incubated for 1 hour with goat antiserum, anti-rabbit, biotinylated (1: 200; Vector Labs, Inc.) for a TH or GFAP immunostained or with biotinylated horse anti-mouse antiserum (Vector Labs, Inc.) for immunostained with nestin or vimentin, then washed and incubated in an avidin-biotin complex (ABC Elite Kit, Vector Labs, Inc.) for 1 hour.Localization of the primary antibody binding was revealed using the diaminiobenzidine peroxidase (DAB) technique. The sections were completely washed and mounted on slides with a lower layer of gelatin and allowed to dry overnight. Finally, the sections were dehydrated, purified and covered with sliding covers as described above. None of the animals used in the study showed adverse effects due to mini-pump implants or surgery injuries. All continued to eat and drink water through the course of the experiments. If the lesion, the infusion, or both were unsuccessful, the animals (n = 6) were excluded from the initial experimental groups and tested separately. A successful lesion is defined as one that causes the complete or almost complete elimination of nigral and ipsilateral TH-IR. A successful striatal infusion is defined as one in which the end of the infusion cannula was successfully fixed in the striatum body. As with the hybridization studies, in all the animals that received infusions in traestriatais of TGFα for six days or more showed a very remarkable reconstruction of cells along the ipsilateral ventricle before the infusion, visible with the theonine stain. In comparison, the contralateral striatum did not show such an increase and was unresectable from that of the animals that underwent perfusion with aCSF. Infusions of EGF in injured animals induced cell expansion throughout the ventricle, but did not induce striatal crest formation. Lower doses of TGFa induced both cell expansion or crest formation but, qualitatively, the number of cells in each decreased. 1. Effects of 6-OHDA Lesions None of the injured animals that received aCSF infusions showed any cell expansion along the ipsilateral ventricle or any evidence of the striatal crest. The injured animals infused with TGFa uniformly exhibited the reconstruction of cells along the ventricle and typically showed the striatal crest. The nigral lesions greatly increased the incidence of crest information compared with non-injured animals (Table 1). 2. Morphology and Persistence of the Crest The midestriatal infusion resulted in a characteristic S-shaped crest that arises from the dorsamedial caudate putamen, sweeping towards the striatum and curving backwards slightly towards the midline of its ventral end. The more dorsal portion of the crest continuously towards the reconstruction of cells in the subependymal region. Typically, the theonine staining was more dense in the dorsal portion of the ridge that paralleled the hybridization of the EGF receptor mRNA. The cellular ridge was generally found through most of the caudal rostral extension of the striatum. The ridge was still prominent in the striatum three months after the infusion pump TGFa was removed. 3. Immunohistochemistry of GFAP The antiserum against glial fibrillary acid protein (GFAP), a marker for astrocytes, failed to stain cells of the striatal crest or cell expansion along the ventricle. Normal astrocytic staining GFAP-IR was found in the medial and lateral parts of the ridge, but was almost excluded from the ridge itself. 4. Silver staining Cells not specifically labeled with a modification of the Nauta method, provided additional information about the cells that contained the ventricular cell expansion and the striatal crest. One of the most striking features was the enormous number of cells making up the subependymal cell reconstruction and the ridge (Figure 8). The cells were densely packed and predominantly fusiform (Figure 8). In the ventral portion of the ridge, elongated cells appeared in the current around the fiber aces in the internal capsule, suggesting that the cells were migrating towards the striatum. 5. Progress in Crest Formation The density of the crest cells allowed tracing their formation using simply theonine stain (Figure 9). All the animals used in the progress of the experiment received lesions with 6-OHDA and with midestriatal infusions of TGFα. At certain points of time before the six of the infusion, there was only a very small reconstruction of the cells in the subependymal region and there was no evidence of the striatal crestal. After six days of infusion, there was a clear expansion of the cells along the ventricle. Nine days after the infusion, the ventral portion of the ridge had begun to appear slightly displaced from the ventricle. Twelve days after infusion, the ventral portion of the ridge was positioned as much as 400 μm from the wall of the ventricle. At 16 days after the infusion, the ridge appeared in the medial triangle, with its ventral portion more than two mm from the ventricle, therefore, the crest originated in the ventricular region and its radial displacement in the stratium superimposed on longer periods of infusion. The estimated difference in distance between the lateral extensions of the crests and the ventricular wall at 12 days and at 16 days after the infusion was approximately 1.6 mm. 6. Immunosteochemistry of Nestin Monoclonal antibodies against nestin, a marker for neuroepithelial progenitor cells, dense collections of fibers through the crests intensely stained (Figure 10). No nestin-IR fiber was seen on the lateral crest, but occasional fibers were seen on the medial crest. The fibers were oriented orthogonally primarily to the ridge. 7. Alteration of the Morphology of the Crest The injured animals that underwent perfusion midestriatally with TGFa uniformly exhibited a striatal crest with an S-shaped characteristic in coronal sections. This morphology was significantly altered in rats with infusions in other areas of the caudate putamen (Figure 11). The medial striatal infusions gave rise to an L-shaped crest near the site of the infusion cannula with the vertical part of the "L" along the ventricle and the horizontal part extends orthogonally from the ventricle to the striatum. Infusion at the lateral end of the striatum stimulated the formation of a linear ridge parallel to the lateral ventricle wall. 8. Immunoestoguimica of Vimentina The antiserum that recognizes vimentin, a marker for radial glial cells, failed to stain any cell in the striatum, the subependymal areas or the striatal crest two weeks after infusion. However, this result is being further investigated since the controls were carried out on embryonic animals, under conditions that can not ensure the elimination of false negatives. . Control of the Crest Position Compared with the cells of the crests in the rats used for the hybridization experiments, if the cells of the crests in the series of the present experiments moved in a maximal way much more towards the ventricle (Figure 12). The difference between these two groups of experimental animals was the time table of infusions and injuries. The animals prepared for the hybridization experiments in if you, received injuries and then underwent a series of behavioral tests beginning around the second week after the injury to confirm the success of the unilateral units typically, these animals did not receive infusions until five weeks after the injury. Therefore, the degenerative process of dopamine and the striatal infusion of TGFα were temporally separated events. In the present series of experiments, the infusions started first; the lesions were not carried out until 48 hours after the infusion pumps were implanted. In these animals, the degeneration of the nigral dopamine neurons, the resultant loss of striatal dopaminergic innervation, and the striatal administration of the growth factor were temporally coincident events. 10. Infusions in Other Brain Regions that are not Es riatum All rats that received infusions in other areas of their brains other than the striatum received infusions of TGFα for two weeks and nigral lesions with 6-OHDA. The intracerebroventricular infusion (ICV) of the ipsilateral growth factor to the lesion stimulated the reconstruction of cells in the adjacent ventricular wall, but did not induce the formation of the striatal crest in any of the animals. The septal and some striatal infusions stimulated the formation of septal crests associated with the medial walls of the lateral ventricles. Septal crests, like striatal crests, were easily detected by in si t u hybridization of EGF receptor mRNA or by theonine staining, but tended to be qualitatively less robust in terms of cell density and number. The corticodorial infusions, that is, infusions so superficial that they did not penetrate the gray body, did not have a discernible effect on the density of the cells along the lateral ventricle. Nor are you dorsal infusions induced the formation of a ridge. The cortical infusions in which the gray body was slightly penetrated stimulated the expansion of cells along the ipsilateral ventricle, but did not induce the formation of striatal crest. These animals exhibited cell densities in the gray body that could be considered callosal ridges. H. TGFa Stimulates Cell Proliferation The present experiments, together with those described in the following, demonstrate that the administration of TGFα was necessary for the formation of cell reconstruction and striatal crest. Not a single animal that received the striatal aCSF infusion-whether it was injured or not-showed no obvious periventricular cell expansion when compared to the contralateral subependymal regions of the infusions or normal animals. It is clear that the anterior brain cells are responding to the strial infusion of TGFα proliferating along the lateral ventricle. Recent studies with six-day infusions of ICV or EGF or TGFa in mice demonstrated a large increase in the number of cells around the ventricle immunomarked with 5-bromo-2'-deoxyrudine (BrdU) or [3H] thymidine, markers for cell proliferation (Cr.-.?j et al., J. Neurosci 16: 2649-2658, 1996). More than 95% of these cells were also positively immunoreactive to the EGF receptor. The violet Nissl Cresyl dyeing also showed an increase in the number of cells around the ventricles in these animals in response to the administration of the growth factor. We first considered the possibility that the expanded populations of cells along the lateral ventricles were from road cells stimulated by the combination of the neurotoxic lesion and the mechanical wound in the forebrain and the infusion of TGFα. It is known that astrocytes respond to a brain wound by proliferating and altering their morphology and functional properties (for review, see Norenberg, J. Neuropha, T. Neurol, 5: 3: 213-220, 1994). Additionally, striatal astrocytes possess EGF receptors (Gómez-Pinilla et al., 1988, supra; Nieto-Sampedro et al., 1988, supra) and are stimulated by TGFα to proliferate (Alexi and Hefti, 1993, supra). In the present study, the antiserum against the glial fibrillary acid peptide (GFAP), a marker for astrocytes, failed to demonstrate an increase in astrocytes of the ventricular region or on the crest two weeks after infusion. In fact, GFAP-IR was widely excluded from these areas. Normal astrocytic staining was observed in the medial and lateral part of the ridge, for example, but few GFAP-IR fibers were observed within the ridge itself. These findings are parallel to those of the experiments with ICV infusions during six days of EGF or TGFa: The GFAP and an additional marker for astrocytes, SlOOß, did not show any significant increase around the lateral ventricle (Craig et al., 1996, supra) . Vimentin can also be expressed by reactive astrocytes (Federoff et al., J. Neurosci, Res 12: 14-27, 1984), but vimentin-IR was not observed in any of the sections examined. The markers for microglia (MAC-1) and for oligodendrocytes (MASG, CNP, 04 and Rip) also did not change significantly (Craig et al., 1996, supra). Therefore, the immunohistochemical evidence showed that the cell expansion induced by TGFa along the ventricle and in the striatal crest was not the result of gliosis. 1. Morphology and Cell Orientation The silver and thionine staining clearly reveals the immense number of cells within the cellular aggregation along the ventricle. The cells were denser and more numerous in the dorsal portions of the subependymal zone and in the crest. The cells were predominantly fusiform, similar to the neural progenitor cells that migrated in the developing brain, with their long axes oriented orthogonally towards the wall of the ventricle (or towards the dorsolateral extension of the subependymal zone that borders the dorsal striatum). The silver-stained cells in the ventral crest segment appeared in the flow around the fiber bundles of the internal capsule, suggesting that they were migrating through the striatum. To determine if the cells were indeed migrating, an experiment of progress over time was carried out to examine the development of the ridge and its location as a function of time after infusion of the growth factor began. 2. Migration of the striatal crest cells The progressive expansion of the cells along the lateral ventricle and the subsequent radial movement of these cells as a dense ridge proved that the cells were actually migrating en masse through the striatum. As such, the crest may not have been an anatomical delimitation between the putative "caudate-like" of rodents and the striatum regions "resembling putamen". 3. Simulation of neural precursor cells Although none of the immunomarkers for mature labeled cells of astrocytes, neurons, microglia or oligodendrocytes of the periventricular expansion or of the striatal crest, since monoclonal antibodies recognize nestin, an intermediate filament manifested by neurothelial precursor cells, intensely stained the process of the cells in the crest and along the ventricle. Reactive astrocytes can also express nestin-IR, but negative GFAT-IR in ridge cells eliminated the possibility that astrocytes formed a significant portion of the crest cells. Nestin-IR has been used in recent years to identify and label neural precursor cells in vi tro and in vivo (Lendahl et al., Cell 50: 585-595, 1990).; Craig et al. , 1996, supra). The stronger nestin-IR in the striatal crest and the lack of immunostaining for the glial markers supports the conclusion that the crest cells are predominantly neural progenitor cells. Thus far, two distinct populations of cells have been identified in the brains of adult mammals that can give rise to new neurons and glia (Morshead et al., 1994, supra). One, it is believed that the relatively quiet population of cells is really a multipotent population of neural stem cells. The other, it is believed that the constitutive proliferating population are progenitor neural cells, offspring of the stem cells. The population of stem cells is thought to remain in the ependymal or subependymal zone and to replenish the population of progenitor cells as they die or migrate elsewhere. The term "neural precursor" is used herein to describe any undifferentiated proliferative cell capable of giving rise to neurons and glia in the adult mammalian brain, whether these cells are neural stem cells or neural progenitors. Previous studies have shown that several neural progenitor cells die in the subependymal area before they can migrate from the region (Morshead and Van der Kooy, J. Neurosci, 12: 249-256, 1992). However, it was recently discovered that many others actually survive and migrate along a path very restricted to the olfactory bulbs where they differ as olfactory interneurons (Luskin, Neuron 1: 173-189, 1993, Lois and Alvarez- Buylla, Science 264: 1145-1148, 1994). They migrate tangentially along the wall of the lateral ventricle in a process called "migration chain" in which the chains of cells that migrate are sheathed by specialized astrocytes GFAP-IR (Rousselot et al., Lois et al., Science 271 : 978-981, 1996). The subependymal zone along the lateral ventricles of the forebrain then is much more than a dormant remnant of the embryonic neuroepithelium. In normal brains that have not been manipulated, they continue to give rise to new neuroblasts that migrate rostrally and differentiate into neurons. Under the influence of the neurotrophic factors of the EGF family, including TGFa, subependymal neural precursors can be stimulated in vitro to give rise to a large number of new neurons, astrocytes and oligodendrocytes (Reynolds and Weiss, Science 255: 1707-1710 , 1992). From these explantation studies, it becomes clear that the highest concentrations of neural precursor cells were found "in the dorsal portion of the subependymal zone, along the dorsal rim of the caudate putamen." There is still more recent evidence that neural precursors they can be stimulated to increase their numbers and produce new neurons and glia in vi vo (Craig et al., 1996, supra) .Double-labeled cells with BrdU and markers for mature glia neurons were found diffusely distributed through the striatum, septum 'and cortex after six days of ICV infusions of EGF and up to seven weeks of survival after infusion, however, no emigration of subependymal cells was observed in the adjacent striatum in this study (framed contrast are the results obtained by the present method) and the number of cells was quite modest compared to the dense cell masses packaged observed in the striatal crest described in the present. On the other hand none of the animals in Craig et al. He received a sufficient infusion to stimulate the migratory mass observed presently and none of the animals in this study received migraine lesions with 6-OHDA, which has been shown here for the first time that they increase the incidence of imigration very remarkably. _ Evidence of the Neural Phenotype One issue that remains is whether the cell within the massive expansion along the ventricle and the migratory striatal crest were indeed neural progenitor cells. Table 2 summarizes the data that support the conclusion that these cells are indeed neural progenitors. Neurochemical evidence showed that they do not express markers for mature neurons, astrocytes, oligodendrocytes or microglia. However, they strongly express a marker for immature neural progenitor cells. They expressed markers for cell proliferation. They were born from the wall of the lateral ventricle where the neural precursors are located in the adult brain of the rodents, expanded laterally and migrated radially beyond the ventricle. In addition, its cell morphology was fusiform and its processes were orthogonally oriented towards the ventricle and the crest, similar to the neural progenitors that migrated in the embryonic brain and consistent with their migration from the subependymal zone. The data summarized in the following table (Table 2) indicate that the cells of the periventricular expansion and of the striatal crest are neural progenitors that are born from subependymal stem neural cells.

Evidence of the Progenitor Phenotype for Expansion and Crest Cells Neurochemistry Abundant expression of mRNA * of the EGF receptor and immunonegative immunoreactivity for GFAP * or S-100β markers for astrocytes Immunonegative for NeuN, a marker for mature neurons Immunonegative for MAG, CNP, 04, or Rip markers for oligodendrocytes Immunonegative for vimentin *, a marker for Radial glia Immunonegaíivo for WiAC-1, a marker for Immunopositive microglia for nestin *, a marker for neuroepiieliales precursors Morphological Somata elongated on ridge oriented from orthogonal to subependymal zone Nestin - IR processed in ridge oriented from the normal to the subependymal area Anatomical It originates from the subependymal zone The highest density of cells is in the subependymal dorsal region Physiological It responds to the administration of TGFα by increasing its numbers 5. Mechanisms of emigration The mass of emigration n of these cells in the striatum can be controlled by the striatal dopamine denervation and by the location of the infusion cannula, but the mechanism of emigration is unclear. The fact that the shape of the ridge can be modified simply by changing the infusion site, initially suggested a chemoattractant effect. It is known that TGFa is a potent chemoattractant for various cell types (Ju et al., J. Invest. Derma tol., 100: 628-632, 1993; Panagakos, Biochem. Mol. Int. _33: 643-650, 1994). Its abundant expression in the perinatal caudate putamen may indicate that it performs a similar role in the development of the striatum. The neural precursor cells in the normal brain are located in a thin region in the wall of the lateral ventricle. The infusions in the middle striatum were closer to the dorsal end cells of this region. Presumably, the cells that bundled towards the striatum would move toward the highest putative concentrations of growth factor at the end of the infusion cannula where the TGFa was released. The characteristic S-shape of the crests in animals with mydriatriatal infusions may have resulted from the saturation of cell receptors in the dorsal segment of the subependymal zone, near the end of the infusion cannula. Cells with saturated EGF receptors could have stopped their migration once they got closer to the infusion site. The cells near the ventral end would see a putative lower concentration of growth factor and would have to travel farther to the infusion center before the TGFa concentration increased enough to saturate its receptors. This differential migration or saturation of receptors could explain the characteristic S-shape of these crests. Infusions in the medial striatum resulted between the L-shaped crests, again in harmony with a gradient / receptor neurochemical saturation effect. In this instance, the subependymal dorsal cells may have had their receptors saturated and stopped their migration before they could have emerged from the subependymal area. Only the cells in the most ventral part of the subependymal region could migrate beyond the ventricle. The lateral end infusions would essentially have presented a putative concentration gradient similar to the cells throughout most of the length of the proliferative region. All subependymal cells migrate a similar distance from the ventricle, resulting in approximately a linear crest, consistent with the idea of a chemoattractant of a neurochemical gradient effect. However, the immunohistochemical evidence from the characterization studies casts doubt on the idea that the simple effect of a chemoattractant could fully explain mass radial migration. Nestin-IR processes of cell migration are not aligned with the end of the infusion cannula, the region of the highest putative concentration of the growth factor. Instead, they were normally oriented towards the ventricle and the crest. This orientation suggested that the cells migrated orthogonally to the caudate putamen, - as do the neural progenitors of the striatal neuroepithelium of an embryo - and not obliquely towards the end of the infusion cannula. Two additional findings discounted the role of simple chemoattractant in the migration of the crest. First, the cells did not start migrating when they were produced; they increased their numbers along the ventricle for a period of more than a week, then they emigrated en masse as a dense leaf of cells. "In addition, the lesion of the ibroslateral substance nigra greatly increased the incidence of migration. More complex package of factors including cell migration These data did not entirely exclude a chemoattraction function in crest migration, but indicated that a simple chemoattractant effect alone could not account for this. having contributed to the radial migration of the neural progenitors in the adult striatuim was the reconstruction of the radial glial scaffold due to the neurotoxic lesion, the mechanical wound made by the surgical implantation of the infusion cannula or both. the migration of neural progenitor cells in various regions of the developing brain They are anchored along the ventricle and extend their processes radially into the underlying parenchyma. They usually become GFAP-IR astrocytes in the early postnatal period once the neuroblast migration is complete and the expression of dimentin and nestin is stopped. The freezing injury of the cortical plate in neonatal rats inhibited radial glial transformation and caused the persistence of glial expression of dimentin and nestin in wounded regions of the adult brain (Rosen et al., Dev. Bra in Res. 82: 127-135, 1994). The injury Kainate of the hippocampus of the adult rat induced glial radial morphology and the expression of nestin-IR and dimentin-IR in astrocytes of the hippocampal subacute area, suggesting that the brain wound could have stimulated a reversal of the astrocytic phenotype in a seat in the brain of the embryo (Clarke et al., Neuroreport 5: 1885-1888, 1994). The present immunohistochemical experiments do not provide support for this phenomenon. Nestin-IR fibers were found in abundance in fibers oriented radially along the ventricle on day nine of the infusion, but at later time points they did not remain any longer along the ventricle. As the crest cells migrated beyond the subependymal region, also the nestin-IR fibers. In addition, immunostaining for dimentin, a specific marker for radial glia, revealed no marked fibers either on the ridge or in the subependymal region. Therefore, it is unlikely that any astrocytes have been reverted to their embryonic glial radial phenotype or that astrocytic reversal has a role in the radial migration of neural progenitor cells. A new way of describing the migration employed specifically by neural progenitors in the brain of adult mammals elucidated the tangential movement of this cell from the subependymal area of the forebrain to the olfactory bulbs (Lois et al., 1996, supra). Neuroblasts that migrate rostrally are densely packed and sheathed by the GFAP-IR astrocytes that surround their highly restricted migratory pathway. Migrating cells essentially form a solid flow of moving cells within a tube of specialized guiding cells. The neural precursors in our experiments migrated as a leaf through the striatal neuropil along a restricted pathway, and were not associated with the GFAP-IR cells. In fact, the proliferative subependymal zone and the cellular crest widely excluded GFAP-IR. Therefore, the mechanism of the migration chain could not account for the radial migration observed in the present studies. Another mechanism that possibly underlies the massive migration of neural progenitors was that the striatum cells may have altered their expression of growth factors, their cell addition molecules or other substances in response to the wound. In this scenario, the striatum may have been stimulated to provide its own chemoattractants or molecules that facilitate radial migration. Alternatively, it may also have induced a very low regulated expression of substances that inhibit migration. Recent studies examine cell adhesion molecules in the striatum and subependymal region and provide a particularly intriguing insight. Immunoreactivity of the adhesion molecule Recent studies examining cell adhesion molecules in the striatum and subependymal region provide a particularly intriguing insight. The immunoreactivity of the highly policialitrated neuronal cell adhesion molecule (PSA-N-CAM) is strongly expressed in the developing striatum of rodents but decreases as mature animals (Aaron and Chesselet, Neurosci, 28: 701-710, 1989; Szele et al, Neurosci 60: 133-144, 1994). The expression of PSA-N-CAM, however, persists throughout the subependymal region of the adult forebrain (Rousselot et al., 1994, Szele et al., 1994, supra). The partial striation deafiation induced by the decortication, very notably increased the expression of PSA-N-CAM and other adhesion molecules, Ll, in the subependymal zone (Poltorak et al., J. Neurosci. 13: 2217-2229, 1993; Szele and Chesselet, J. Comp.Neurol. 368: 439-454, 1996). In the human brain, PSA-N-CAM expression is lower in normal elestriatum, but increases in striatum with Huntington's disease, particularly in the subependymal zone (Nihei and Kowall, Ann Neurol, 31: 59-63, 1992) . Of particular interest are the changes that occurred in the expression of fibronectin mRNA in the striatum after unilateral frontal partial decortication (Popa-Wagner et al., Neuroreport 3: 853-856, 1992). Fibronectin is from a number of molecules that have been shown to support neural migration in vi tro (Fishman and Hatten, J. Neurosci, 13: 3485-3495, 1993). Hybridization of fibronectin mRNA was increased to a maximum level of 72 hours in the portion of the striatum immediately below the wound cavity. This early increase was interpreted as a component of the short time of the wound healing process. The expression of fibronectin in the larger ipsilateral striatum followed a long-term increase, reaching its maximum around ten days after the injury. This secondary increase was interpreted as a striatal response to the one of aference. The increase in expression in the other two mRNAs encoding N-CAM and alpha tubulin followed only spatial and temporal patterns related to early wound healing. The tenth peak day of striatal fibronectin mRNA expression after deaferentiation corresponds well to the delay in the migration of the ridge following the striatal dopamine denervation in the present studies. The delay of the highest expression of fibroneptin mRNA may help to explain why the progenitor cells of the invention did not start to migrate radially until about the ninth day of infusion, and because, when they finally migrated, they migrated en masse. In animals where the infusions and lesions were separated- for several weeks, the maximum lateral migration distances at two weeks of infusion were markedly reduced. This observation is also consistent with the highest transient point in the striatal expression of fibroneptine. In the few animals with ridges that also did not receive migraine lesions, mechanical wounds of the upper cortex may not have stimulated sufficient expression of fibroneptine in the striatum to facilitate migration. The fibroneptine can then be upregulated in response to the dopamine denervation of the ipsilateral striatum at the time it could temporarily facilitate the radial migration of the neural progenitors of the subependymal zone. Another possible influence of the radial migration of the neural progenitors in the adult striatum can come from a secondary effect due to the cellular addition molecules. Infusion of N-CAM into the brains of adult rats that received dagger wounds in various areas of the brain, including striatum, and measured astrocytic proliferation (Krushel et al., Proc. Na ti. Acad. Sci. USA 92: 4323-4327, 1995). The astrocytes released factors that inhibited the growth of the neurite and could therefore inhibit the neural regenerative response. Therefore, the denervation of the striatum and the associated increase in subependymal PSA-N-CAM could have released the inhibition of neural regeneration. The improvement of the migration effect in the denervated striatum of dopamine may also have been directly related to the loss of dopaminergic innervation. During the embryonic development of striatum, immature neurons developed in the ventricular region and migrated radially (Bayer, 1984, supra).; Bayer and Altman, prog. Neorobiol. 29: 57-106, 1987). The developing migration of striatal neurons takes place before the innervation of dopamine by the middle brain afferents. Stimulation of dopamine D2 receptors in neurons of the hypothalamus greatly attenuated mRNA expression in TGFa and pituitary growth (Borgundvaag et al., Endocrinology 130: 3453-3458, 1992). Although inhibition of dopamine-mediated TGFα expression by a receptor has not been studied in the subependymal zone, it is consistent with the incidence of depression of migration in non-injured animals. Therefore, the innervation of dopamine during development can inhibit the migration of striatal cells as long as the dopaminergic innervation of the anterior brain is re-established. Striatal dopamine may also contribute to the down regulation of striatal TGFα early in development while dopaminergic afferents become established. The denervation of adult striatum dopamine can mimic through the striatal cells some of the chemical tails of the local environment that is normally seen only in the developing striatum, for example, a reduction of the ligands available for the dopamine receptors manifested in striatal neurons. The striatal innervation of dopamine has also been linked in a reciprocal manner with the expression of molecules in the extracellular ground substance by astrocytes (Gates et al., J. Chem. Neuroana t. _6: 179-189, 1993). Interestingly, TGFa is selectively elevated in the striatum of PD patients (Mogi et al., Neurosci, Lett, 180: 147-150, 1994) in a manner similar to elevated expression in the embryonic striatum. If striatal TGFa is regulated by dopamine innervation, this increase can be related to the reduction of striatal dopamine and the consequent release of the expression of TGFa inhibition. Whatever the underlying mechanism, the ongoing experiment proved that subependymal cells could stimulate the increase of their numbers and migrate radially en masse to the adjacent striatum in the adult rat brain. Experiments in which the location or dose of the infusion of TGFα was varied, showed that the movement of the striatal crest and the large number of cells involved could be controlled. Characterization experiments provided abundant evidence that subependymal cell expansion and dense striatal crest were composed of neural progenitor cells. The importance of these findings is discussed in the following, together with their potential application for the treatment of human neurodegenerative diseases and traumatic brain injuries. The invention has been explained with reference to specific examples and modalities. Other modalities may be suggested to those skilled in the appropriate art until a revision of the present specification. While the foregoing invention has been described in some detail through illustrations and examples for the purpose of clarity and understanding, it will be obvious that certain changes and modifications may be practiced within the field and the appended claims.

Claims (25)

1. CLAIMS 1. A method for treating a patient having a neurological deficiency, characterized in that it comprises the method (a) contacting a neural progenitor cell of the patient's central nervous system (CNS) with a polypeptide that binds the growth factor receptor. epidermal (EGF), the dosage of the polypeptide being sufficient to stimulate the proliferation of the neural progenitor cells, and (b) direct the progeny of the proliferating progenitor cells to migrate en masse to a region of the CNS in which the cells will receive and function in a sufficient way to reduce the neurological deficiency.
2. 2. The method according to claim 1, characterized in that it further comprises contacting the cells with a compound that stimulates the proqenia of the proliferating neural progenitor cells to differentiate.
3. 3. The method according to claim 1, characterized in that the neurological deficiency is caused by a neuroregenerative disease, a traumatic wound, a neurotoxic injury, ischemia, a developmental disorder, a disorder that affects vision, a wound or a the spinal cord, a demyelinating disease, an autoimmune disease, an infection or an inflammatory disease.
4. 4. The method according to claim 3, characterized in that the neurodegenerative diseases can be Alzheimer's disease, Huntington's disease, or Parkinson's disease.
5. 5. The method according to claim 3, characterized in that the ischemia is associated with a fulminating attack.
6. 6. The method according to claim 1, characterized in that the polypeptide that binds the EGF receptor is amphiphulin (AR), betacellulin (BTC), epidermal growth factor (EGF), epiregulin (ER), the binding of eparin of EGF-like growth factor (HB-EGF), Shuannoma-derived growth factor (SDGF), growth factor of Shope fibroid virus, myxoma growth factor, growth factor-1 derivative of teratocarsinoma (TDGF-1), the alpha factor of growth transformation (TGFa) or bovine growth factor (VGF).
7. 7. The method according to claim 1, characterized in that the polypeptide that binds the EGF receptor is TGFa ..
8. 8. The method according to claim 1, characterized in that the neural progenitor cell is contacted in vivo with a polypeptide that binds the EGF receptor.
9. 9. The method according to claim 1, characterized in that the neural progenitor cell is contacted in culture with a polypeptide that laces the EGF receptor.
10. The method according to claim 1, characterized in that the migration is directed by contacting a cell, along, or at the end of a desired migration pathway with a compound that increases the expression of the cell adhesion molecule or the molecule of the extracellular fundamental substance.
11. 11. The method according to claim 10, characterized in that the compound is TGFβ.
12. 12. The method according to claim 10, characterized in that the cell adhesion molecule is fibroneptin.
13. The method according to claim 10, characterized in that the cell adhesion molecule is laminin.
14. 14. The method according to claim 10, characterized in that the compound is applied along the path between the neural precursor cells and the location to which its progeny are directed in their migration.
15. The method according to claim 1, characterized in that the migration is directed by contacting cells along a desired migratory pathway with a compound that inhibits a signal that occurs naturally along the path, the signal being that a signal that inhibits migration naturally occurs.
16. 16. The method according to claim 1, characterized in that the migration is directed by a mechanical breakdown of the tissue in the CNS.
17. 17. The method of compliance with the claim 1, characterized in that the migration is directed by neurochemical obstruction of the activity of the cells in the CNS.
18. 18. The method of compliance with the claim 2, characterized in that the compound that stimulates differentiation is the retenotic acid or a neurotrophic factor derived from the brain.
19. 19. A method characterized in that it comprises a treatment to a patient having a neurological deficiency, the method (a) contacting a neural progenitor cell of the patient's central nervous system (CNS) with a polypeptide that binds the factor receptor. epidermal growth (EGF), the dosage of the polypeptide being sufficient to stimulate the proliferation of the neural progenitor cell; (b) directing the progeny of the proliferating progenitor cells to migrate en masse to a second region of the CNS; and (c) contacting cells that have migrated with a compound that stimulates differentiation.
20. 20. The method of compliance with the claim 19, characterized in that the compound that stimulates the proliferation of neural stem cells and the compound that stimulates differentiation are administered sequentially.
21. 21. A pharmaceutical composition characterized in that it comprises a polypeptide that binds the epidermal growth factor receptor (EGF) and a compound that stimulates the differentiation of neural progenitor cells.
22. 22. The pharmaceutical composition according to claim 21, characterized in that the polypeptide that binds the EGF receptor is TGFa.
23. The pharmaceutical composition according to claim 21, characterized in that the polypeptide that binds the EGF receptor is TGFa and the compound that stimulates the differentiation of the neural progenitor cells is a neurotrophic factor derived from the brain.
24. 24. The method according to claim 1, characterized in that the wound to the central nervous system is a wound to the spinal cord. The method according to claim 1, characterized in that the wound of the nervous system is a wound to the retina.